From all that I have researched I have come to the conclusion that they are better off being alone. They do not crave having company like some animals do. They are perfectly content having the full run of the house themselves
. Also, if you try to pair them up, it can be difficult and then you can end up with 2 that can't get along and have to be seperated anyhow.
Better off alone when in doubt unless your purpose is to breed or something like that.
As far as yours not doing much, as the other poster said, they need time to acclimate. But they don't "do" a whole lot anyhow other than basking, hangin out, maybe some climbing the walls, etc. Not sure if you are expecting more than that
Just give him some time.
good luck!
Renee