Thought this would be simple...

I’m trying to copy an old cassette to my computer (MacOS Mojave)
Bought a Cassette Converter and downloaded the Audacity software (1.3.12) that came with it. Been at it for hours and can’t get it to work.

That version has been obsolete for years. The current version is 2.3.0 and is available here:

This part of the manual may help: