There are several methods to accomplish this.

Looking at Dan's chordsheet, if you want a chord populating the minus bars prior to Bar 1 or if you want to use the method Matt and Lloyd outlined in these measures, you can use any measure to create the data you want to occupy those bars and copy/paste or move/paste from the Audio Edit Window and that data will sound out and play the same as the Grace Notes in Dan's example.

I would consider the bars prior to any measure containing the Am7 in Dan's example for the Chords to use --- Bar 8, 10,19/20, and 23/24
or you can create any chord or progression for those slots and place them in the minus bars at the beginning of the song.

These chords or grace notes will not show up in Notation, the Piano Roll or Chord Sheet but the track or tracks edited will play correctly.

To enter exactly what you want, you can enter the notation or piano roll to transcribe it and use the Playable RealTracks feature or likely a midi or SuperMidi instrument.

Attached Files (Click to download or enlarge) (Only available when you are logged in)
Chord in the -1 measure.jpg (158.21 KB, 85 downloads)
Audio Chord before Bar 1.jpg (158.63 KB, 85 downloads)
Playable RealTrack Notation.jpg (153.34 KB, 85 downloads)
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