If you are using Docker for your Peertube, you need to modify the `docker-compose.yml` file to open port 5269 of the `peertube` container, so that the outer world can connect to it.
You need to add [DNS records](https://prosody.im/doc/dns) allowing remote servers to find "room.your_instance.tld" and "external.your_instance.tld" components.