Installation
The Subsurface Portal will be delivered as a Server Object Extension (SOE) file. To install this file on the ArcGIS server:
Open the ArcGIS Server administration page, etc http://myhost.com/arcgis/manager
Click the Sites page
Click Extensions item on the left side of the page.
Click Add Extension and select the Subsurface Portal .soe file
Once you have access to the Geocap Viewer widget follow the ArcGIS Portal documentation on how to add custom widgets in Web AppBuilder or Experience Builder.