You wait until you receive a message from eBay to say the buyer has paid.
When this happens, the buyer receives a 6 digit QR code, they must bring this with them for you to scan as this is your only proof the item has been collected, and also releases your payout sooner.
You can send the buyer a polite message to say you are awaiting confirmation of payment from eBay, and if they haven't done so already to please go to eBay checkout and pay there. They may also be new, and having won the auction, may not release they now do have to go and pay for it!
Also, remind them to bring that code with them, because you will not / cannot release the item without this code.
@jgfj5-86