So what we see of stars is the energy released from the nuclear reactions inside their cores and then radiated from the surface. Since most stars are VERY far away, the light takes anywhere from a few years to millions of years to reach us. So the star light that we see is very old indeed. There are many different kinds of stars. They come in many sizes and colors.
Some stars even orbit around each other.
We call these binary stars. If you have any more questions about stars, please ask us to tell you more.