The easiest way to accomplish this task is to start with a 'new' project.

then:

Select: FILE -- Select: Open Audio w/ chords. From the BB file open dialog box that opens, navigate to the mp3 file you want to use and BB will import that file into the BB audio track, run the ACW feature and import the chords into the Chord Chart Page.

At this point, styles are disabled so it does not matter what style is loaded. This is to allow you to play the imported mp3 file without any BB style playing so that you can play the mp3 and make any corrections to incorrect chords. This is helpful because you can make changes and not have to wait for BB tracks to regenerate with each change you make. Once you have the chord chart correct to your satisfaction, choose and audition styles (RealTracks or Midi) and open the style of choice. You will have to enable the styles at that time and then generate the backing tracks. Use the mixer to balance the audio file with the BB generated backing tracks. I find it helpful to have the audio track a little lower in volume than the BB tracks. This helps to compare that you have the chord chart correct. You will also have to open the Song Settings and uncheck the 2 bar ending selection in order for the BB generated tracks to end the song correctly. If you want to fade the song, use F5 Bar settings which will allow you to fade the BB Tracks and the audio tracks.

BIAB 2025:RB 2025, Latest builds: Dell Optiplex 7040 Desktop; Windows-10-64 bit, Intel Core i7-6700 3.4GHz CPU and 16 GB Ram Memory.