Hi I installed the CB yesterday and created a new registration for my homepage.
Now I want to fit the registration form to the design of my homepage. But I can´t find the code where I can do this. I need different divs to order the fields of the registration form. Where can I do this?

It would be great, if someone can tell me where I change these things.

To change the pure ordering of the fields, go to CBs field manager and change their order there.
To find out which CSS to change in which file you can use tools like Firebug for Firefox. Or do a forum search as I believe it's been posted numerous times before.