I've been in multiple rehabs and I've found the 2 main focuses are either the 12 step program, or working, building character, and getting down to the real cause of your issues.
The 12 step programs are easier, but the character building ones are so much more rewarding in my opinion. Daytop rehab facilities are all over north America and I'd recommend those IMO
As the old man above me said, rehabs main focuses are to help you build coping mechanisms other than using drugs, and healthy alternatives to every day situations