Hi Pete,
Just to add to what Matt has said ...
I've set up the Realtracks you list as follows.
1. BASS = Realtrack #700 (electric bass)
2. PIANO = Realtrack #365 (acoustic guitar fingerpicking)
3. GUITAR = Realtrack #1118 (12 string strumming)
4. STRINGS = Realtrack #1875 (soloist mandolin)
When looking at the picture below, notice that BASS,GUITAR and STRINGS have green lines under them. This indicates that these Realtracks have notation available. The PIANO, on the other hand, does not have a green line thus there is no notation available for RT #365.
Let's say I want to see the notation for the soloist mandolin. Since this is on the STRINGS track, I would do the following to see that notation.
1. Open the Lead Sheet View by clicking on the green button with two notes.
2. Now click on the "S" (for STRINGS because that's where the mandolin solo is sitting) that I've circled in red and it's probably best to view it in "Fake Sheet Mode", which I've also circled in red.
Don't worry if this all seems a bit confusing. Sooner or later, it all falls into place
All the best,
Noel