Networking in games is a very complex skill, and will make a complex project. So this page will try to give you information which you can use to create your own example.
The easiest way to install LiteNetLib is to create a new MonoGame project. Then in the Tools tab, choose NuGet Package Manager. Then choose Manage NuGet Packages for Solution.
Click on browse, and then type LiteNetLib into the search box. This should find the latest version (currently 0.7.7.2), click install. Finally in your Game1.cs, add the code below to the using section: