Oh how brilliant is that! Very exiting!
I would say let him settle inside your home for as long as you can. Calm, as little visitors as possible at first, no outings to busy places or unnecessary car journeys, etc. Basically become a bit of a hermit for a while. If you can keep him in one or two rooms with access to the garden, that can become his territory, rather than overwhelm him with the whole house straight away. remember he must have been confined to a very small space in kennels. Avoid exiting, stimulating games at first, and anything 'in his face', don't put your face in his face, don't try to touch his head, etc. The more relaxed and undemanding you are, the better, it's hard to not be happy and exited to have him but try to ignore him, turn your back to him, this is body language he understands and shows you are not a threat.
And always, always, take your cues from him, do not force a cuddle, not even a pat, let him come to you (super important with visitors too). Give him as much cuddles as he want but let him ask for them. You can sit quietly next to him reading, or something, let him inch near you and cuddle you first before you respond. I am mad so I talk and say things like you're ok now, I look after you now, you can relax, everything's fine, lots of food for you here, etc. 👀
Ours is on about 8 meals a day at the moment because he is so underweight and anxious about having food. It's made a huge difference to his behaviour.
It's wonderful to see him gain confidence. Good luck OP, keep us posted please!