Installing Ground Model
Installation Instructions
To install the Add-In:
Make sure ArcGIS Pro is not running
Double-click he Add-In file with the .esriAddInX and continue with the install
Start ArcGIS Pro
Confirm that the installation was successful by clicking Project → Add-in Manager and observe that it lists Ground Model as an add-in.
Alternatively you could place the Add-In file in the folder you have assigned as an Add-In folder for ArcGIS Pro. To manage this open ArcGIS Pro and go to Project -> Add-In Manager -> Options and add the directory.