Ah... well, based on your description, I suggest you first look at the structures of posts to see if you got it down and then hop into a casual to begin with, then move up to advanced. If you're OK with combining depth and character development in with your 5-10 paragraphs, you can do advanced. If you want I can dig up some starters for you (preferences would help in selection).

[url=http://www.roleplayerguild.com/topics/4958-a-new-users-guide-to-the-guild/ooc]This guide may be of use to you[/url].

Welcome to the guild :)