Shattered, it's a little rude to get on someone else's thread and post your own questions. In the future, make your own thread.
In the tabs on the top of the screen, click "groups." You will be taken to a list of covens. If you click on the coven's name, it will take you to a summary of it. At the top, if the coven is accepting applications, it will say so. Click that to apply. Scroll down and read all the rules before applying oo a coven, though. Also, most covens have questions you need to fill out that are included on the summary.
As for spells, you can write your own easily.