He needs to go to another home where he's the only cat. That will stop the inevitable fights (and almost inevitable 'spraying' as each cat tries to mark the house as his/her own property). Further it will avoid the problem of trying to keep free access available (e.g. via a cat flap) to the original cat, while keeping the new arrival locked in for a while.
He needs somewhere without to much traffic and, ideally, a cat flap. However it will be important to keep him locked in for a fortnight or so, while he gets to know his new home. (Don't forget the litter tray!).
When he's ready to venture outside, try to watch him (and quickly bring him back if he's getting a little too adventurous) on the first couple of occasions but leave him to it after that. Don't worry, he'll soon work out where he fits into the local feline hierarchy and find his way around.
Chris