A good thing would be to read the rules:
The RolePlay Board Rules.
Other than that, it's about imagination, you can create a story, and enact it. Be that in first of third person. It's really story telling. It's about expressing fantastical imaginings, making thoughts come to life. Perhaps peruse the threads and get a feel of what it's about. The board seems very lacking in threads seeing as it underwent some changes, but I do believe there are still a couple of storylines going on.