Programming a stand writes your unique receipt link onto its NFC tag. You do it once per stand, from your phone, in under a minute.
Programming is permanent. Once a stand is written it's locked, so it can't be changed, re-used, or pointed at anyone else's business — including by someone who picks your stand up off the counter. Have a blank stand ready before you start.
Go to More → NFC stands → Program new stand.
Tick I understand programming locks this stand permanently, tap Start programming, then hold your phone flat against the stand until it says "Stand programmed and locked".
Tap Test it — the app creates a sample receipt, then you tap the stand like a customer would. See the sample receipt? You're live.