Hi!
Stereo Tool and Perfect Declipper are not editing programs, that's why there's no feature to import a file. Of both tools there are two flavours: the stand-alone version (for realtime processing) and the plugin version (for production).
- You could use the former if you want all your music to be declipped on-the-fly regardless of what you're listening to. In this case you'd need another application to "catch" the audio from the playing application and route it into Stereo Tool. Since you're on a mac I would recommend checking out Audio Hijack and Loopback.
- The latter (the plugin) is easiest if you have specific files that you want declipped. The VST mac plugin of Stereo Tool runs in any 64-bit editing software that supports VST plugins. This could be something like Adobe Audition but also free software like OcenAudio. You would open the file in your editing software and then apply the plugin as an effect.
I hope this helps you. Hans is a busy man, I don't know how you contacted him, but next time send an email to support (at) thimeo dot com. We're with more than just Hans
Or use the forums of course!