அண்டத்தில் உள்ளது பிண்டத்தில் உள்ளது 
(There is a micro-cosmos in every body)

Its not 6 a.m. because the clock is showing 6 a.m., but the clock is showing 6 a.m. because it is 6 a.m. The cosmos is just like this clock. It is merely an indicator, but not the instigator of the happenings. These celestial objects neither know nor care about our existence. They keep revolving around and transiting the skies as per the law of causation. We, humans, with our innate narcissistic nature, imagine their purpose is to serve us. We merely derive our personalized dosage of attributes like morality, courage, intelligence, allure, wisdom, emotional stability, patience, etc. handed over to us in this life, from the celestial snapshot at the time of our birth, popularly knows as birth chart. These birth charts are like the railway/airline timetables, you need to know some basics before you can start inferring what it is trying to say.

There are two fundamental layers in a birth chart, namely, zodiac signs and placement of planets. These are like the X and Y axis of a birth chart. Understanding these two layers lay the foundation before someone can venture into other advanced layers like Aspects (drishti), Transits (gochara(m)), Constellations (nákṣatras) , Dashas (calendar of planetary influences), Yogas (Conjunction of planets), Argalas (interference), Karakas (reason for a cause) and so on.

About planets, there is much less left to imagination as these are physically existential and perceptible objects in the skies, so we'll start with the planets.

On a full moon day, ocean is roaring and on no moon day, it is absolutely placid. Our bodies constitute more than 72% water, the exact same kind of water found in ocean. Obviously, this water will respond to the full moon in the same way. People with inclined sensitivity can feel it. Hence, the mentally inclined people are often referred as lunatics (lunar - moon), intoxication (soma - moon) is also related to moon. Since moon is very close (1 light-second away from earth surface), the impact is conspicuously felt. Moon's influence is tightly related to our emotional self, how we feel within ourselves.

Next such strong impact is from sun. Sun is the significant source of light in our solar system. All the life forms on earth depend on sun. We cannot see air as it lets light pass through without any resistance. We see an opaque or translucent object, because it blocks light and reflects it. Hence sun drives our personalities, meaning, how we project ourselves and how other see us. Sun drives our confidence and morality. Two key things to adapt and co-exist in a society.

Whole earth wobbles every year by 11 degrees left and right due to gravitational pull of venus and jupiter, which results in summer and winter solstice. When a 1024 kilograms of earth can wobble, we are a spec with no power to resist the influence of venus and jupiter. Venus pulls us towards indulgence while jupiter pulls you towards wisdom. This wobble doesn't need much explanation, as we've all gone through the debate of good or evil within ourselves numerous times. Jyotiṣa personifies Venus as teacher (acharya) of demons (shukracharya - shukran). Jupiter is called the guru of angels (devas).

Similarly, mercury is responsible for our intelligence, street-smartness, quick wit, eloquence, sharpness. Mercury is small, quick and bright and it imparts the same qualities with its influence. In Sanskrit, bōdhi (budhi) means intelligence, mercury is called Budha(n). The famous word, 'Buddha' means an intelligent one, again derived from the same planet name.

Mars is called mangal, meaning, masculine, auspicious, aggressive, brave, red (sevvai), hot and considered to be a commander (while Sun is considered a king). It imparts the same qualities with its influence. When you see a person with abundant courage, people who are very assertive and stand-up for themselves and others often, consider their mars is pretty strongly placed in their birth chart.

Saturn, the largest and slowest and farther planet to have a significant influence on earth induces large impact, slows things down, resists change and pulls us toward conservativeness. This is also the planet responsible for our patience and discipline.

These seven planets Sun, Moon, Mars, Mercury, Jupiter, Venus, Saturn serve equally well in the evolution of an individual but the nature and dosage of their characteristics they impart on an individual depends on their current position and their position at the time of person's birth. Other objects like Neptune, Uranus, Pluto and even the moons like Titan of Saturn, called Gulikan (or) Maandi have an influence on everything on earth.

There are two other celestial objects called north lunar node (Rahu) and south lunar node (Ketu). These are not physical planets but two points in the sky, where the moon's orbit (around earth) and earth's orbit (around sun) intersect. These two are pretty much the salt and pepper of the vedic astrology. While the influence of physical planets are pretty well defined, these two objects disrupt the status quo. Rahu is the bringer of sudden surprises, crazy swings, ups and downs, like a rollercoaster ride. Ketu inflicts renunciation, leads one towards eternal search, breaking cycles of repetitive patterns of life. If not for these two, the so called evolution might be super slow that we will complete miss to notice it.

The seven planets along with these two pixels, a total of 9 grahas in the space drives the abilities and life-events of the living beings.

To understand zodiac signs, visualize a 12 spoked stationary wheel as shown in the below diagram. These 12 sectors are the zodiac signs. At the time of birth, the zodiac sign peeking at the east horizon is called the raising sign, ascendant or lagna of the birth chart. That sign becomes the starting point of the birth chart and it is referred as the first house of the birth chart. Since earth revolves around itself every 24 hrs, each rising sign stays the same for two hours. Example, at 2 a.m. the sign on east horizon was Pisces, at 4 a.m. it'll be Aquarius and at 6 a.m. it'll be Capricorn and so on.
In the above diagram, earth (center part) is revolving anti-clockwise, so it would look like Aries (1st house) is raising on the east, while Libra is setting on the west (7th house). So Aries becomes the ascendent for anyone born under this situation. As long as one understand the planets and zodiac signs, they begin to understand the birth charts. Unlike earth the planets revolve slower than 24 hrs. Hence the planets will sit clinging to a zodiac sign for a while. Moon stays in same sign for 21/4  days, Sun stays in same sign for a month, Jupiter stays in same sign for a year, saturn stays in same sign for 21/2 years.

Then to venture deeper, influence of 27 constellations, called nákṣatras, is like doing the masters in vedic astrology and is for more dedicated learners. The pyramids of egypt is aligned pointing towards the stars of Orionis (Mrigashīra) constellation, because it is believed to be the portal for higher realms. Meaning, when the soul, leaving the body is directed towards stars of Orion, it goes to the higher realms, commonly known in the east as liberation (mukthi) of the soul. Hence, the soul doesn't have to take another earthly form again. These stars, though far away from earth, due to their sheer size, they influence on the solar system is commendable. Hence these nákṣatras were given a sacred place and great importance in vedic astrology.

Millionaires don't care about astrology. Billionaires do! - JP Morgan

As soon as we start understanding these, our immediate curiosity is to jump towards prediction. Its not that easy. When you see someone visually challenged, you can assume, they cannot drive a car. Similarly, when you see someone with weak mars, you can infer they are going to be timid. a weak mercury meaning, not very street-smart. Apart from this, its not easy to infer much. Prediction is more of an art, than just science. Its the ability of the person to ingest multiple reasons from several layers of a birth chart, and put things together. It is not for everyone. I myself am curious about the science behind it, but not much interested in prediction.

This love for prediction and people running behind everyone who claims they can predict is the reason why the whole art and science of Jyotiṣa Vijñāna has been deteriorated. People pay abundant wealth chasing the desire to know what is going to happen to them, without due diligence in validating the authenticity of the person claiming to do so. By doing so, they produced more posturers and ruined it for the future generations. A word of advice, such rich science and knowledge is never for sale. Anyone who is an absolute master of such ancient sciences, will never sell it for meager worldly things. The moment someone claims such worldly things, be aware, he/she is not an absolute master but an incomplete or worse a posturer.

Use this basic knowledge of customized cosmic plan for you to work towards where your desires lead you. At the same time they reveal your unexplored potentials and also the limitations. Accept both humbly and it'll slowly lead to acceptance of diverse people of varied potential equally.

manasaiva pure devaḥ, pūrva-rūpaṁ vipaśyati,
anumīmāṁsate 'pūrvaṁ, manasā bhagavān ajaḥ - Bhṛgu-saṁhitā
(One receives an inferior or superior body at the discretion of the Paramātmā (Supreme Personality of Godhead).