Setting up Tap to Pay is the owner's job. Taking the payment is somebody else's. This is the field guide for affiliates, volunteers and seasonal staff: the eight taps, where the tap actually happens, and what to do when it sticks.

Shopify's help docs tell you to start inside the POS app. You cannot. Tap to Pay is activated in the Shopify admin app first, and only then does it appear in POS. Here is the setup in the order that actually works, with screenshots of every screen.