Confirm the shared requirements
Check that everyone is using the same edition and a compatible current release. A Java world is not a Bedrock session. Make sure the internet or local network connection is stable before treating a timeout as a broken save.
Joining a Bedrock friend
Sign in with the appropriate Microsoft account, add the host as a friend and have the host open the multiplayer world. From Play, use the Friends tab and look for a joinable friend. A direct friend-hosted world is only available while the host is online; a Realm uses an invitation and a separate hosting arrangement.
If the world does not appear
Check account multiplayer permissions, especially for child accounts, and the platform’s online subscription requirements. Update the game and ask the host to verify that multiplayer access is enabled. Use the official connection guidance before reinstalling the game or moving world files.