<< Now there is a problem, such as A, B, I can control and change the drum by myself.
But it can't control instruments such as guitars, which is more random. The drums of the A section and the B section are different, obviously, and can be controlled by yourself, but the instrument cannot. Right-click and click the color vertical bar, there is no instrument selection. >>

<< Is there any way to control it, or that this is random? >>

There are several ways to control it. I'll show you the method I think is the fastest and most way; Use the RealTrack Medley Maker.

Here are the steps:
Project Setup:
01. Open a new project
02. load the Heeldig.sty Demo file
03. Change the number of Choruses from 3 to 1 (this isn't necessary but it speeds up generating the song)

This demo will control and change Guitar 2 > 2625 Guitar, Baritone Electric, RhythmBluesBoogieBass and Licks ev 100
Medley Setup:
04. Select the Guitar 2 Track in the Mixer
05. Open the RealTracks Picker
06. Verify that Guitar 2 is the selected track and then click the Medley Button

Create the Medley:
07. Set the "Change RealTrack at every" bar to 8 Bars
08. Verify the first slot has Guitar 2 > RT2625 filled in
09. In the second slot, type in 2501, select the 2501 guitar and OK
10. In the third slot, type in 3351, select the 3351 guitar and OK
11. The RealTrack Medley Page should look like the attached screen shot (without the arrows)
12. Click OK to exit the RealTrack Medley Page
13. Confirm the Medley is active by observing small writing beside the Medley Button
14. Close the RealTrack Picker
15. Generate and Play the Heeldig.sty Demo

The result is every 8 bars (which in this SGU file also changes PartMarkers), the track containing the 2625, Guitar, Baritone will change to the next Medley instrument. The first change is Bar 9 - (RT2501, a soloist instrument that's also a Baritone Guitar played by Brent Mason) and plays for 8 bars. The second change is Bar 17 - (RT3351, a Rhythm instrument that's also a Baritone Guitar played by Brent Mason) and plays for 8 bars. These instrument changes will continue to rotate every 8 bars until the end of the song.

Charlie

Attached Files (Click to download or enlarge) (Only available when you are logged in)
RealTracks Picker.png (274.87 KB, 265 downloads)
The RealTracks Picker
Medley Instrument Selections.png (21.5 KB, 265 downloads)
Medley Instrument Selections
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.