Clay Doh works with Blender’s Asset Browser. There is no Addon to install.
In Blender, open an Asset Browser window. (Or change any window to an Asset Browser type using the button at the top-left corner of each workspace window).
Once inside the Asset Browser, you will see a slightly bigger drop-down button at the top-left that lets you choose asset libraries. Click on it to see the list of available libraries, and select ‘Clay Doh’ from that list.
Now you will see all the Clay Doh assets in the Asset Browser. Make sure to set the Import Method to ‘Append’.
Everything is sorted in catalogs here, simply drag-n-drop. :)
Materials can be dropped directly on models in 3D Viewport
Shader Nodes can be dropped in the ‘Shader Editor’ window
Objects can be dropped anywhere in the 3D Viewport