It’s time and patience
. And building up trust. Keep talking to him - they can sense when someone is caring and safe.
At some point you could get him out for some taming sessions - they usually will walk into a tube with a smelly bit of food at the far end and you can lift him out that way (hands over the end of the tube) either into a playpen area or box which you can carry to a safe area for out of cage time and taming.
It does usually take two weeks for any hamster to fully settle in a new cage. Meanwhile don’t clean or move things around. So it doesn’t stress him. Spot cleaning a pee corner once a week is fine.