Care to tell me how one does this? I've scrolled through the possiblities and only see crew module, dynamo, etc. etc.

This likely has an obvious answer, but once I took the ion-bolt module off the flagship I was never able to put it back on. Even after buying information on improved weapons from the traders I can't arm the main ship. I'm sure I'm just missing something from the interface so if someone would point me in the right direction...