GUIDs (UAC User ID = a GUID) are unique identifiers used within the game or different programs (like anti-cheat programs) to recognize players. ClanBase can use these to avoid freelancer usage in official matches.

Step 1:
Download & Install UAC2 here.

Step 2:
Launch UAC2 once installed.

Step 3:
Click The "Create an Account" button to create your account.

Step 4:
Enter in the account details you want and press "Register".

Step 5:
IMPORTANT: Check your email, you will have an email regarding your registeration. You must use that link and confirm your email address before you can use UAC.

Step 6:
Enter your newly created account details into the login box and push "Login".

Step 7:
Log into UAC Website and click My Account (Top Right)

Step 8:
Take note of your user ID and go to guid properties page and enter your UAC User ID.