The beta versions can be downloaded and installed from here:
https://www.waveworks.dk/flow/beta.html
You may of course test in any way you like, but here is some inspiration for what you can do:
- Open various CSV files that you have on your computer or from the web and check that they look right.
- Go through the features in the feature matrix table on the About page and check that they work as expected.
- Go through the newest features in the What's New chapter in the Help documentation and check that they work as expected.
- Read the Help documentation and check that the various commands work as described.
- Challenge the formula engine and the undo/redo functionality, since they have been the most complicated functions to implement.