When you siege you can END your movement AND siege in the same turn if there was no battle in the walled city space right? But then it says you need to activate the general to do another siege action... I know it may sounds dumb... but activating a general is the same as when you Move it but you don't move it you siege instead right? So for Hannibal you play a card for CPs but dont move it just siege right? It is just because under the CPs use section it says MOVE A GENERAL (not activate him). So activate is the same thing as moving him?
Yes. When you activate a general to move, you can move him from 0-4 spaces. Moves of 0 work the same way as moves of larger numbers (that is, moves that actually move the general), and you can siege after them just as you can siege after longer moves.
You could move him to bring more units in the space from an adjacent space and siege againt with him right???
Usually, yes. But if the army conducting the siege is exactly 5 CU, and it includes a Consul, then you can't pick up adjacent CU's without losing any accumulated siege points; if the Consul moves, he has to take all 5 CU with him, and as soon as he moves off the city space, the siege points are lost, even if he moves right back in the same impulse.