Minecraft LAN isn't working?

So this is my first time trying to set up any kind of server I want to play minecraft with my sister and we decided to use the Yogscraft complete pack on the At-launcher. So i read up that when you hit the LAN button in-game it gives u the IP and port #s but when i start it up all i get is the port # so i tryed using ipconfig and all that in the cmd window but that didn't work keeped getting connection time outs.
I have almost ZERO idea in any terminology of internet configs and all that so googleing didn't help me well. ALSO i heard that it should just show up in the server window but that doesn't work also something called Hamanich or something like that appeared when i went to google do i need this?

SO i short if anyone can give a detailed walkthough Step-by-step that would be AMAZING

Sorry about bad grammar btw English is a 2nd language

Minecraft LAN is just for people on the same Wi-Fi.
Your sister will go to the multiplayer part and then you scroll down to the lowest and click it.
If that doesn't work I have 1 more thing
I use it with my friends
https://gratisserver.nu/
When you go on it then you open a account and go to your email and you should activate it
Then open your server