Hello and welcome to Iwaku!
I'm Kitti and it's good to meet you.
You are new, indeed, but we'll soon fix that up~
While you're here, though, I'll give you some places to check out to further your goal of being involved in roleplays!
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!
You should definitely still take a look around the site since those links barely scratch the surface, though.
If you need any help, please do ask!