Steamworks Complete comes with a number of samples scenes that demonstrate common functionality.
As a GitHub Sponsor you will have installed Steamworks Complete via the Unity Package Manager
You can simply select Steamworks Complete in the Unity Package Manager expand the "Samples" drop down and then import the Example Scenes ... this is also where you will find the uGUI Tools
You will see a Samples folder imported along with the asset.
uGUI Tools for Steam is not currently available to Unity Asset Store users.