I think he means "where can you get the custom maps". I know that most of it is "Done in Animation" or something, but I ASSUME it's "copy and paste animation to a background". You know, like CGI, but inserting into a game.
If it's what I think it is (and what others also think it is, a lot of "what map" questions on youtube), than the custom maps have to be used, he has to run/stand around in GMOD or HL2 to use the shots for later when he pastes the animations in.
If that's true, than users would like to know what maps he's using. If it's not true, then I withdraw what I just said.