Help! Clueless of how to play Locally

Me and my sis so badly wanna play locally on the same router. If any of you know how to do this, please let us know. And in case if any others dont know, they get their answer too. Thank You and we gladly appreciate it.

 

The only way you'd be able to have your sis and you play on the same server would be to do the normal port forwarding route, and then use your local IP for your sister to connect (Assuming you are using your computer for the connection). For example instead of giving her your public IP (Which would look something like 79.25.142.113 something like that) you would give her your local IP, which always starts with 192.168.1.xxx. If you're using your computer you would start up the server, and then start up the single player client confusing I know. But then when the server is running you select multiplayer and enter 127.0.0.1 for the IP to connect to your server using your own machine.

Forwarding your port isn't too hard, people just make it seem difficult with insanely large walls of text that describe almost non important information.