To install the Satellite Imagery for ArcGIS Add-In after downloading:
Browse to the folder location where the install file (*.esriAddInX) was downloaded on your computer.
Double click on the file to open the ESRI ArcGIS Add-In Installation Utility window.
To continue click Install Add-In. The Add-In is then copied to the default location and installed. A copy of the install file will remain in the original download location as well, this can be deleted after installation is complete.
If ArcGIS Pro is open, exit and restart the application. The Add-In should now be available for use.