If you are coming to this page for the first time, you'll see the form into which you can enter your username and some other settings. It is best to choose a WikiName (like FirstnameLastname) as username to get your changes and signatures link back to your WikiHomepage. Entering your email will enable you to get notifications on page changes.
If you click on Create Profile, a user profile will be created for you.
The "ID", shown in the response page, gets saved as a cookie in your browser for the system to recognize you. Same cookie can be stored on other machines you might use. So jot it down! Or cut and paste the URL shown above, after you created your profile. Alternatively, if you provide your email you can have the system send you the ID later
Logout clears the cookie created at login. Login enables you to gain access to your user profile if you somehow lost the cookie or are on another machine. Save just updates your profile.