LAN world not showing up
LANs work when a host hosts the world on a local network for others to join. The lan number is not useless.
Go to the play multiplayer screen, and click "Direct connect."
You should then be offered an entry called "Server Address" Enter the number displayed when you open to LAN.
I haven't used LAN for a while but I think this is the solution. Another thing is make sure that both are connected to the internet.