Open a doorway.
Register a world, put one verification file on its host, and connect. You need a saved Pocket Beyond account and a public HTTPS hostname. The alpha allows three worlds per account.
Your server configuration
Copy this into a private .env file on your world server. Never serve it to browsers or put it in source control.
Prove you control the host
Serve this JSON at /.well-known/pocketbeyond.json on the exact origin you registered. Keep it available for re-verification.
Your worlds
Start with a working world
Download the multiplayer starter, extract it, install its dependencies, and copy the server configuration into .env. The starter README explains proxying HTTPS and hosting the verification file.