HEY! haha Well, I just learned some of this today, but I'm still learning. If you click on "My MIbba" at the top of your page, scroll down to the third subtitle that says "Profile" and click on "CSS." Ok, then there's a page with the code that you already have on your page, which is the defult layout. Well, go down a little ways and there's a thing that says ~Layouts
Click here to use one of our pre-made layouts.~ On the middle of the page. Click that and you can chose a layout that's already made for the site. That's what I did.
Ok and for the thing for the story, well I guess it doesn't have cover art for it like testriffic did, but they call it an Avatar. The same subtitle as what I told you above, but click on "Avatars." Browse a pic of what ever it u want and it'll appear when you post stories and comments and stuff. You can do the same thing with the Message board too, but that's a different subtitle.
*Sorry if this is so long and confusing, but I tried to do the best I could. Comment/Message me back if you what me to tell you more* :)