Want to therapy certify my dog and volunteer my dog; where can I do this?

Hello everyone!

When I was a therapy grad student, I wanted to get my dog certified as a therapy dog and volunteer him at nursing homes or at hospitals, anywhere that there is the need. I’m no longer pursuing counseling, but I would still love to do this. Does anyone have a trainer they recommend to certify my dog and also, does anyone know where they need dog volunteers?

Thanks!