Most people know their sun sign and stop there. The sun is one twelfth of you. A natal chart is the other eleven twelfths, plotted across a circle that froze when you arrived. It is the closest thing astrology has to a fingerprint, and once you read yours, the generic horoscope you grew up with stops being interesting.
What a natal chart actually shows
Three things at once. Where each planet was sitting in the sky (the sign), where it was sitting in your life (the house), and how the planets were talking to each other (the aspects). All three matter. Read only one and you will misjudge the whole.
Why your birth time matters
Without a time, you get a chart that is roughly correct: your sun sign, your moon, the planet placements. But the rising sign and the houses depend on the exact minute. They shift by a degree every four minutes. The difference between a rising at 29 Libra and 1 Scorpio is the difference between two very different people walking into a room.
What to read first
Sun, moon, rising. That is the trio that tells you most of what you need on the first read. The sun is the engine, the moon is the inner weather, the rising is the door. Once those three click, everything else (Venus, Mars, Saturn, Mercury) starts placing itself.
What it cannot tell you
Your chart is potential, not fate. It will not tell you who to marry, when to quit, or what number to bet on. It will tell you which patterns keep finding you and what those patterns are made of. The rest is yours to do or not do.