To add other Actions in:
you have a Button 3 name
Code:
Gui, Add, Button, x212 y40 w100 h30 gButtonBB3, Action

and the Button function
Code:
ButtonBB3:
winactivate,ahk_class TBandWindow
Send,  {Space}
Return

so BB Action button 3 is sending "spacebar" key
and activates the Biab window with "winactivate,ahk_class TBandWindow"
to get the ahk_class of any window run "WindowSpy.ahk" in the AutoHotKey folder or right click on the little green icon with the white H in the system tray > Window Spy.

If we want to change that action to Unfold
Code:
Gui, Add, Button, x212 y40 w100 h30 gButtonBB3, Unfold

Code:
ButtonBB3:
winactivate,ahk_class TBandWindow
WinMenuSelectItem,ahk_class TBandWindow , , Edit, Song Form, Unfold (convert to 1 BIG chorus)
Return


Copy the menu path names exactly, like if they have ... ,
";" semicolon in front of a line disables the line.
You can edit the autohotkey.ahk script in any test editor like notepad.
Save it and double click to run it, make sure the script is closed first,
look in the system tray for the little green icon with white "H"
you can also right click "Reload This Script"

That's just accessing menus if you want to add more advanced functions look at the Biab Chord Picker Tool script.

Biab Track Injector for Reaper
Free Biab Chord Picker Tool