Download the Geocap installer from https://geocap.no/t/downloads
After downlaod run the installation file Geocap-8.1.x-64.msi
Click your way through the installation wizard.
After installation start Geocap - for example by searching for Geocap in the search field of the Windows taskbar
5. If this is the first time Geocap is running for this user on this computer, the following message appears:
...
6. Geocap will then prompt you with a dialog asking you to login. At the same time it should open a browser window with the login option.
For more information on licensing see Licensing Geocap 8.1.x and above