Download and install Adobe AIR: https://airsdk.harman.com/runtime
Download the Progressimo.air file.
(Note: if you browser adds ".zip" to the filename when you download it, remove it. The file extension should be ".air".)
If it doesn’t launch:
Progressimo will automatically check for updates from time to time when it starts up (and you can do this manually as well from the Help menu). It will also handle the downloading and installation of new versions (asking for permission each time).
Read the introduction to Progressimo and its main features, then read up on some key concepts.

A simple progression model
The help project (Load "Help project" from the Help menu) is a good way to start learning what Progressimo does.
These are listed on the main page.
If you’re stuck on any of the concepts, refer to the rest of this user guide.