Unity of Command Forums

Sorry for what is sure to be a silly question but I've done the tutorials and looked at the manual and cannot for the life of me see how to move supply depots.

I know how to make new ones, add and subtract trucks, but how to make them move is a mystery.

You cannot "move" them just like that. Subtract existing hub to zero. On the next turn, trucks will be available (or immediately if you are in the battle preparation phase).
Then just place another hub at a different location.