Done! Electric fan speed control...I'm not an electrician in any way, shape, or form

[workingonit]

I previously installed a 3000 cfm Flexalite fan in place of the viscous fan (which was failing). I "redneck engineered" the installation, but it's been perfect for the almost three years I've used it, so I think I'm overdue for throwing another mod at it, when I take apart my engine bay (soon), for a thorough smoke test, parts inspection & replacement, and general cleanup. I'll make the wiring for my fan look more orderly, at the same time.

While there, I'm planning to install a cheap "DC Brush Motor Speed Controller", sourced from Amazon (with good reviews), to be able to lower the fan speed when it's not necessary to run it at full rpms. Currently, it runs full beans all the time, roaring even at idle at lights, and probably totally unnecessary at highway speeds. I most notice it when I'm pulling in my driveway, and opening the swing gate...it's loud. I bought a
ICQUANZX DC Brush Motor Speed Controller DC10-55V Forward Reverse with Digital Display&Fan Inside 40A-60A https://www.amazon.com/dp/B081YYG5MG...roduct_details with 40amp continuous/60amp max capability for the 18amp Flexalite fan (my first post in bcredliner's thread on electric fans).

From what I've seen and read, this should be able to lower the fan speed when I want it, but I'd like someone with electrical/electronical experience to chime in, and tell me that I'm not going to burn out my primary fan, just as summer approaches (auxiliary fan just won't be enough, alone).

I plan on mounting the unit on a small plastic clipboard, attached to the seam where the carpeting stops, rising onto the console (driver's side). It'll be modular, with proper easy to remove connections, so if it suddenly fails, I can quickly make the fan run on the already installed wiring.

There's a three-position switch attached to the unit (forward-stop-reverse), but I'll only want it set to "forward" of course (though my fan is a "puller" by design), and I wonder if I accidently select the other positions, will the unit cause damage to the fan motor, running at full speed? Of course, the unit came with no instructions.
which is forward, which is reverse?

I'll probably mount the unit to the backside of the clipboard using Velcro strips, and also use them to attach the rear of the clipboard to the console carpet, for steadiness.
lightweight control unit assembly should be out of the way and accessible

I already have a "lockbox" mounted to the front of my seat, in a black bag, which will obscure the speed control unit from sneak thieves, I hope. But then, I hardly ever park where they might be prevalent.