Bowling takes two screens. This page, on a laptop, is the lane; your phone is the ball. Open this address on a laptop and scan the code it shows.
Your phone is the ball. Pair it once, then pass it round. No server is involved at any point, including this pairing.
Use the camera app. It opens the ball page — same Wi‑Fi as this laptop.
The phone will display a second code. Hold it up to this laptop’s camera.
Two codes because an introduction goes both ways, and a QR only points one way. The way round that is a server in the middle, which this deliberately does not have.