I have a BR-8. It is an 8 track digital recorder. It has 64 "virtual" tracks which means, each of the track faders have an additional 8 "Phantom" tracks. How would you use these? Well, you press the "V-track" button next to the record button and the screen displays the tracks and you need dial in what track you want to either record to or hear in playback. In other words, say you are trying to lay down a guitar solo on track 5 and you get part way through it and you really screw up...instead of erasing it, just go to V-track 2under track fader 5 and re-do your solo....say you screw up again or just don't like the solo....go to V-track 3 under track fader 5 and so on....each of the 8 tracks have 8 additional "virtual" tracks underneath them. When you done, you need to pick what V-track you want and then set it up so that v-track is one of the "final" 8 tracks.
I don't what machine you have but the BR-8 uses a "time-Value" dial to navigate around these tracks and v-tracks.....
One more thing.....ifyou have BR-8, the manual does explain very clearly how to use V-tracks. If the other Roland / Boss recorders are anything like the BR-8 then I would assume the instructions would be clear.
Good Luck.
Telegib.