On October 12, there was a snapshot of phase 1 of the ONProver campaign. On October 15, $ON token transfers will stop, so make sure to claim them.
Go to the activity website, open the Rewards tab, connect your wallet, and stamp the test tokens. You will need some MON test tokens for claiming:

Participating in airdrops is your choice and your risk. We don't guarantee any rewards. Connect your wallet only to official websites. If someone asks you to send crypto – it's a scam.