A birth chart will show the snapshot of where each planet is in the sky, but then within this snapshot, the sky will be divided up into 12 equal slices for the 12 zodiac signs, so every planet will fall within a certain zodiac sign.
Now, this is where things can get a bit complicated. There are three main parts to interpreting a birth chart: the planets, the signs, and the houses. A birth chart will show the snapshot of where each planet is in the sky, but then within this snapshot, the sky will be divided up into 12 equal slices for the 12 zodiac signs, so every planet will fall within a certain zodiac sign. For example, if the planet Venus falls within the Sagittarius slice, you would say you have a Sagittarius Venus.