Welcome to our insanity :)
You already filled out your on and offs so that is a great start. As said poke around a bit, see what each subforum is about. Then look in the one on one solo roleplays wanted and look at the various threads, get a feel for how people advertise what they want to play and then have a think about what you want to get started with storywise.
Perhaps you see an idea that tickles your fancy, then send a pm to that person about it and see what happens. Or your muse gets inspired and you want to make your own thread. I found that structuring my idea thread in a very personal manner has helped me get replies from likeminded people. Remember we have lots of different tastes and styles here, some want quick and dirty sex where posting speed is more important then post length, others.. well they prefer longer more flowery posts but less concerned with speed. Try and find out what you prefer :) If you like longer posts having your idea thread be basically:
i want the following
doggysitter/tentaclemonster from space
well that might attract the people you are perhaps not interested in.. If you get what my poor tired brain is trying to say :)
Don't be afraid to ask quests, or ask for help :) We are all friendly... well.. most of us. *evil grin*