I often do things a little different from Bob, though my main use is just for practice and I oftren want the melody for the first time through.
If I just want accompaniment, I'll enter the chords into BiaB as Bob does.
If I also want the melody, then I usually create a lead-sheet in a notation program (I use MuseScore, but whatever best suits you), then export as MusicXML and import that into BiaB onto the Melody track. My lead-sheet normally has only the basic vocal melody and the chords names. By using the lead-sheet, I also get the chord names imported into BiaB. There were some problems with that a little while ago, but I think it's now fixed. I'd better say that some people like the BiaB note-entry method. Personally I find it frustrating ... perhaps just a familiarity issue.
You can import onto other tracks, but you'ld need then to 'freeze' the track to stop BiaB regenerating.
After that, I think rest of what I do is very simiular to Bob's.
Trying to do the melody with RealTrack data doesn't really work well, as RealTracks are pre-recorded phrases. You can use 'Editable RealTracks' to adjust a few notes, but all that's doing is switching from the RealTrack to sforzando for those notes, then back to the RealTrack. It does, though, use samples from the RealTrack file and tries to blend them, so in principle it should match well.
If you can use a MIDI controller, you can use that to enter notes.