I've not used this function in BIAB before. I can get so far and then I'm doing something wrong.....
- In BIAB choose File, Open Audio.
- Navigate to your audio clip.
- Once it's in BIAB, click on the icon that says 'Dm' on it. This is the chord converter.
- A popup asks you if you want to open this, click yes.
- A large chord conversion window opens, you'll probably have to pull it smaller, mine filled the screen.
- Click the button 'OK, send to BIAB'.
- A pop up appears saying Bar 1 is not set. Click the 'Yes' button.
- The chords used in the clip now appear in the main BIAB window.
- You may get a pop up telling you about the key.
After this it all goes to pot. I choose a style and the resulting MIDI doesn't seem to sync with the audio. Maybe you're supposed to delete the audio and go from there as you now have to the MIDI chords.
Maybe try the BIAB forum?