How to get Smush Pro?

I downloaded WP Smush and wanted to upgrade to Pro. At this point, I don't need anything else, just WP Smush Pro.

I have no clue as to how to get it installed on my blog. None whatsoever. Is there a way to just install it as a plugin? I keep getting prompted to download the dashboard (which I'm still not clear on what it does). I downloaded the zip file but I can't see any exe file with which to install anything, nor can I find any instructions.

I'd really appreciate clear and simple instructions on how to get WP Smush Pro going. I have the regular version, I just want to unlock the Pro features for a reasonable fee. I don't need templates, forums or any other feature.