Going back to that moment of birth and the universe that is still suspended in time around you, you now look towards the eastern horizon. The way the sun rises over the horizon, so do the constellations if you are looking for them. Your rising sign is the constellation that was rising over the horizon at that exact moment. This sign will be considered the sign of your first house, the starting point of the 12 houses.
The houses are not physical objects in the sky. You will not look out and see them the way you can see the planets or stars. Due to this, the invisible division of the skies into 12 parts needs a starting point. This point is your rising sign.
The houses represent different areas of life. When a sign and/or a planet fall in a certain house, it means that that area of life is being infused in some way by the traits of that sign or planet. As with the 12 signs, there are more houses than planets. So although all planets will fall in a house, not every house will have a planet in it.
In addition to the sun, moon and planets, there are also various points often included in a birth chart. These points are usually not physically there, but more so an imaginary point in space that is calculated based on the locations of these other physically present parts of the chart. But as with the planets, these points also fall “in” a sign and house.