I don't have any experience with pacmans other than what I've read on here. But, you should be using treated tap water for soaking, distilled does not have the minerals and nutrients that he needs. Most people on here use seachem prime for treating it. - Good thread regarding that - http://www.frogforum.net/vivarium-te...hing-else.html

The substrate looks a bit dry, it should be damp but not so wet that you can squeeze water out of it.

Make sure at least 3 sides of the enclosure are covered while he adjusts to his new home.

Here is a care sheet to look through - Frog Forum - Pacman and Horned Frogs - Ceratophrys - Care and Breeding

And hopefully someone with personal experience with pacs stops on soon