What you build on a colony is also vitally important. The more factories you have, the greater your production capabilities. The more research stations, the faster your research and the more advances you can make, etc. This is limited by the number of workers you have available, so once again, it s a good thing to keep your population happy and reproducing. Once a colony is reasonably large and self-sufficient, you can assigned management of it to a computer AI using a number of predefined expansion paths, such as production, civilian growth, technological advances or military fortification.
Battles take place in space, around planets and on the ground.
Battles in space are fights to the death, with little purpose besides establishing your superiority. To conquer a planet, you must attack it with one of your fleets, comprised of fighter support and capital ships, which also carry tanks for the consequent ground assault. Victory in space will mean the opportunity to launch dropships carrying tanks down to the surface, where you will engage enemy tanks and defense installations for a battle that will decide the ownership of the colony. If you win, the planet, its colony and its resources are yours. Of course, now you ve got a really pissed off enemy race on your hands.