Contest runs from March 7th 2023 until June 7th 2023
You can see referrer stats under every user name, I did a screen capture of the stats as of today will paste it below.

The plugin or as phpBB likes to call it "Extension" updates real time once the referred individual has made a post, shown at the bottom of the index page her.
If you want the referral link there are simple instructions listed at the bottom of the pages here where it says "Referrals" or the direct link is here
If you have any questions or comments post here.
Peace