execute shell script

I have written a script for an installer that will check if cygwin is installed, install it if not, and then install FSSW (the software I am working on). Once this is done, a shell script named KALI.sh needs to be executed. I tried to do this with the following line:

ExecShell "run" '"$INSTDIR\tools\audio\KALI.sh"'

One of my coworkers told me the only way to run that script is through cygwin, but how do I write a script that will open cygwin and run the file automatically?

Exec '"$somepath\cygwin\bin\bash" --login -ic "$INSTDIR\tools\audio\KALI.sh"' or something like that