Look at what Action01: is doing,
to do it line by line you can add a line

MsgBox, Paused

or comment out (disable) the other lines with ;

this way you can get one step at a time working.
So below it should pause after opening insert bars dialog.


Action01:
winactivate,ahk_class TBandWindow
;Send, {RIGHT}
;Send, {LEFT}

WinMenuSelectItem, ahk_class TBandWindow, , Edit, Insert Bar(s)...

MsgBox, Paused

Sleep, 300
Send, 4
Send, {ENTER}
Sleep, 300

Clipboard := "[Chords]`n|a)%|%|%|%|%|%|%|%|`n[ChordsEnd]" ; "`n" = new line


;winactivate,ahk_class TBandWindow
Send, ^+v ;send ctrl+shift+v to Biab (paste chords from clipboard)
Sleep, 300
Send, {ENTER}


Return