Firstly welcome to the game and the forums.
This process you are looking for is called relocation.
Well firstly you need to have an outpost under your control for 24 ticks (orange number in the box or on the orders menu to view) Your colony must also have 72 control ticks.
You will need to have at least 50 energy and some oil (maximum required 10000)
However if you relocate your protection automatically ends and any units that are not in the main base will be left behind
You may be conquered before this happens and therefore your control ticks will be reset however being conquered isn't the end of the world it has no effect on you aside from the fact that you can not conquer other colonies.
If you need anymore assistance feel free to ask any questions or you can apply for a mentor at our AANC system here: viewtopic.php?f=401&t=1036