Once logged in, click on "Account Settings"

Then click on "Settings" of 'Edit Profile'

Now place your backlink in the "About You" field using the format as shown in the pic. Once done, click on the "Save" button.

Now, visit the URL as shown in the pic where you are supposed to click on the "Share" icon to find the URL of your backlink.

Voila! Your backlink is ready.