How to delete (Undo) a track
1.) Record a track.
2.) If you don’t like that track, hold down the Track Button (lower right) until Undo shows (flashes) and then release the button. The track will be undone. At this point you can press record which will set it up so when the beginning of that track comes around it will automatically record what you play. Alternatively, if you decide you liked the original track you can hold down the button until Redo appears. Release the button at that time and the undone track will come back.
With An Overdub:
1.) Record a track
2.) Overdub that track
3.) If you don’t like your overdub then hold down the Track button until Undo appears (flashes) and then release the button - your overdub will be undone and Overdub should appear. Pressing Overdub now allows you overdub a new part.
4.) If you don’t like your overdub AND the original track layer then hold down the Track button. It will show undo, which will undo your overdub. If you keep holding it down it will show overdub and then undo again which will undo the original track layer leaving nothing recorded on the track. Above the button should then show Record which you can press and the track will start recording at the beginning of where it started previously.
With Multiple Overdubs:
1.) Record a track.
2.) Overdub that track with another layer (overdub).
3.) Once you now overdub a third layer (overdub) the last overdub you played will be merged with the original track layer and CAN NOT be separated from it anymore.
4.) If you don’t like the third layer (overdub) you just recorded you can then hold down the Track button and Undo this layer. If you continue to hold down the button and release it when Undo flashes again your last overdub layer AND the original track layer that has been MERGED with the first overdub layer you did will also now be Undone. Now there’s once more an empty track. Or you can hold down the button and REDO your last overdub or hold it down longer and REDO your last layer and the original track layer with its now-merged first overdub layer.
Every subsequent overdub will cause the previous overdub to be permanently merged with the overdubs that came before it and the original track layer.
So you can never have more than two track layers and they both can be Undone so as to leave you with a track where something completely new can be recorded. As to when that track starts, I haven’t explored or understand well the options but the Settings section allows different options for this. I hope this helps.