For most people, just adding LondonGaymers as a friend will be enough.
Once you've done that, you'll see the game as a joinable friend.
🛈 Like Bedrock, this should be considered beta so may not be super reliable. If the game isn't showing as online come back a short while later, tag a mod on Discord, or try one of the methods below.
If you're still stuck or don't have any friend slots, then you may need to follow the instructions below ⬇️
This method might take a little more setup, but we'll take you through it.