I saw your post in War (war between pokemon and humans)
It works pretty simple, you go to the RP's ooc thread ((in this case, Foreshadows of Hoenn(OOC threads are normally in the Roleplay Lounge section)) and post a Sign-up where you detail everything that is asked. Most of the time you can find an outline in the first post made by the Game manager under the section SU.
Just fill out the info, and if it's approved by the you're in, if not just go and fix what is asked.
Hope this helps. If you need more help, you can just ask.
P.s. The human side is really outnumbered in War, but you can still be a pokemon if you want.