I see now. Each weapon needs its own ammo.

I couldn't find any documentation. Incidentally, pressing Tab to switch weapons doesn't work for me. I have to manually place a weapon in the first slot in order to use it.

OK, thanks.

How do I get a construction robot to repair or construct something?

thanks, I get it now.

How do I get my character to be able to fight aliens with personal weapons? I can't find the way to do it.

I am playing on a randomly generated map, and there doesn't appear to be any oil reserves anywhere nearby. Is that possible, or do I need to travel far and wide to find oil?