You will need to add the complete path to the .sh file. Mine is in my Home directory, so I can call it from there.
Hang on a minute and I'll fire up a vm and get you the file and path.
Here you go.
Depending on your VBox version number, you will need to use something like this in the terminal IN THE VIRTUAL MACHINE, of course:
That may not be your version number, so check what you have and make changes accordingly.
(My apologies, by the way. I did something I try not to do: assume that you understand exactly what seems obvious to me. I should have done a better job of explaining it in the first place.)