The cat may now be hungry so provide food, but remember that an upheaval can upset a cat's system and make it sick. Your cat may have to live in that room for a few days while you try to organise the rest of the house. When he is allowed to explore the rest of the house, keep external doors and windows shut. You will need to keep your cat indoors for two or three weeks to get used to his new home. If your cat is to be allowed outdoors, familiarise him with his surroundings by escorting him using a harness a lead for the first few forays.
Some cats settle in quicker than others.
He will need plenty of reassurance and petting while settling in and it is critical that he wears a collar and tag, at least until he has settled in.