Reserve hanger and huge maps

Hi

I recently started playing this game and I can't find how to enable huge maps and also when playing as TEC Rebels I can't get the reserve hanger to work. It says that there it needs plasma weapons but I can't see a system that is a Gauss weapon. But I can't see one to install in the battleship. The other one is it must be a carrier but that won't install on a carrier either.