The address claim feature uses your wallet's ability to cryptographically sign a message proving ownership of a specific address. To claim your address enter all three requested fields (if the address field has the incorrect address, click the 'Address Claim' link on the menubar to clear it).
For QT Wallets: Click 'File' and select 'sign message'. Next paste your address you are signing for in the address field, and the name you would like to register in the message box (make sure it is identical including letter case). Next click 'sign message' and your wallet will generate a signature. Copy the entire signature (you can use the copy to clipboard button). Input your address, the exact name your signed for, and the signature into the input field on presstab.pw. Click submit.
For daemons: ./hyperstaked signmessage addressgoeshere nametosignfor