If you want to use your code as build-in excel addin, you can only share it to use as xlam file.
Then autorun procedure is not nesesery when you want to use it any time (not first after run).
In your code I can't find references to activeworkbook to be sure that change 'll do on right instance (many opened excel's files and selection commend can be insufficient).
But VBA code is not all your concern.
Anyway, You should add to this add-in menu structure in XML to get icon to run.
You can start from "Custom UI Editor For Microsoft Office" app. That is a free MS application to add code to ziped excel files.
I build add-in, with MS icons to use selected picture by names in your ribbon.
Regards