<< so in my case I figure it would take me hours of study to finally manage to put together that piece in three minutes. >>

Not really. You already know 'how' to do it but just didn't know before now it could be done. You know how to assign Part Markers and what Part Markers do. So after you decide what instruments you want in a Style, what soloists and fill instruments you want to add to the Style you've chosen or created, it's a simple matter of saving the Style variations as custom Styles that are used throughout your song by assigning and placing them to come in and out using Part Markers. If you want two (or more) instruments to play simultaneously, it's just the matter of saving a custom Style with all the additional instruments to play and when they play. You can use existing Styles without any modifications or modify every existing Style in any configuration you want.

<< It sure doesn't look like all that's going on just from looking at that image. >>

You're right. You're giving instructions to BIAB and it executes it all in the background.

BIAB 2025:RB 2025, Latest builds: Dell Optiplex 7040 Desktop; Windows-10-64 bit, Intel Core i7-6700 3.4GHz CPU and 16 GB Ram Memory.