What some people do is create the RP in the main forum (or the sub-forum where the RP would go) and then also create an OOC. Link to the OOC in the set-up posts of the RP so people can go there to chat about th RP & ask questions, post profiles, etc . . .
There are also a lot of role plays that have no OOC, and everything just goes in the RP thread - it's all about how you want your RP to run :yes: