in the device manager, did you click on ports to expand it?
if you did, you should see an unknown device and you can start from there.
I had the exact same thing happen to me when I first used them.
Instructions on this site are for official Arduino boards
What is "official"?!?! I can copy "official" ones and start selling. Try to review the license they used.
I always use those Chinese clones for a small fraction of the price, even though I'm Italian (it's an open-source project anyway, right?) and I don't like exaggerated prices of copy-paste-ers in some countries where citizens pay huge taxes and the bourgeoisie way of thinking here (the more expensive, the more reliable).
It's just a 2-layer PCB with a handful of components soldered and a bootloader in the microcontroller chip. Everything is open-source and total illiterates can make it with the right tools. I love "cheap labor" until they have some kind of democratic revolution or something.