Where/what is the user control panel? Is it on the website?
Each member has their own User Control Panel (or User CP). You can find your User CP under the forums main banner where it says 'Welcome back, [username]. You last visited: Today (User CP - Log Out)'.
In your User CP you can change your membership and profile information (such as password, email, avatar, signature, and the way you'd like to use the forum, etc...).