How to add server in Minecraft 1.12.2 in Xbox One?

I am running 3 servers using phantom and I can join them with Xbox One. phantom can be run on Linux, Raspberry Pi or Windows.

Description:

phantom makes hosted Bedrock/MCPE servers show up as LAN servers, specifically for Xbox. You can now play on remote servers (not Realms!) on your Xbox with friends. It's like having a LAN server that's not actually there, spooky.

How does this work?

On Minecraft platforms that support LAN servers, the game will broadcast a server ping packet to every device on the same network and display any valid replies as connectable servers. This tool runs on your computer - desktop, laptop, Raspberry Pi, etc. - and pretends to be a LAN server, acting as a proxy, passing all traffic from your game through your computer and to the server (and back), so that Minecraft thinks you're connected to a LAN server, but you're really playing on a remote server. As soon as you start it up, you should see the fake server listed under LAN and, upon selecting it, connect to the real Bedrock/MCPE server hosted elsewhere.

For an optimal experience, run this on a device that is connected via ethernet and not over WiFi, since a wireless connection could introduce some lag. Your game device can be connected to WiFi. Your remote server can be running on a computer, a VM, or even with a Minecraft hosting service.