Uh... all right.
Hi there and welcome to Iwaku.
I'm Kitti and it's good to meet you.
Since you're new to us, I have some awesome links for you. This is where you can sign up for the roleplays found in Modern, Scifi, Fantasy, and sometimes Mature. Generally, they will have you post a character sheet in their thread, a new sheet for each roleplay! You can also start signups for a roleplay of your own here.
This is where you can find jump in games, which typically have no sign up thread. You just start posting!
This is a good guide to some of the most useful places on the site for roleplaying, but you should still look around for yourself, too.
If you have any questions, please do ask.