Impossible to use Library mode

Hello, I have read all the posts about issues with library mode but still I is not working for me. I have created a new user, because I am using mac os with my iCloud account but when I try to use this new user in the apple tv, it does not work. What I am doing wrong? Can any one do a tutorial, step by step? I have installed in my apple tv infuse and plex, and I really prefer to use infuse but I also like the library of plex.
Thanks

You may also want to check and ensure SMB is fully enabled on your Mac.

A few tips for doing this can be found in the macOS section of this guide.