Make custom usercp page...
 

I would like to make a custom user cp page with some custom functions in it. So first, how would I go about adding a menu item to the UserCP Navigation?

Second then I want to create a custom page in the usercp with my custom functions. So when I click the new link I can go the this page apart of the usercp, so only registered members can access, because the custom functions are based on what user is on that page.

Thanks for the help! Hope this isn't to confusing.

You can add a menu item by editing USERCP_SHELL. For the content - see the usercp.php file for an example implementation.