There’s really nothing to install, so you may start by opening the provided Blender files.

Sturdy is real-time, so set Viewport Shading to Rendered everywhere.

Fire up the Shader Editor, play the animations if available, look around, move around the available lights and play with the sliders on the node groups.

Sturdy is based on two base node groups for the Shader Editor, Sturdy and Sturdy+. You will use and reuse these node groups to make new materials and compositions, each with your own custom adjustments.
SPOILERS: Both node groups are actually the same. You should only use Sturdy+ if you really you want to micromanage the shades of the underlying magic palette. Keep in mind that there are simpler ways to get great colors with Sturdy.