Ubuntu – Trouble getting usb wifi to work – AC600 Realtek rtl 8811AU

I am…in over my head, and I apologize if this has already been asked and answered, but I did search, and had no luck (lots on rtl8812..). I used to use Ubuntu some back around when 12.04 came out, but haven't really done much since then and don't really know how to do anything. I bought a new (older, refurbished) desktop and wanted to get it set to dual boot win10 and Ubuntu 16.04. I also bought a usb wifi card, as the desktop did not come with one.

Specs: HP desktop, i5 processor, 8 gb ram, 2 tb hard drive
USB card (I realize I should have concerns about compatibility as I searched the Q & A on amazon and it says the newer kernels may not have support): https://www.amazon.com/Adapter-EDUP-Wireless-External-Antennas/dp/B01CCMUN8C/ref=cm_cr_arp_d_product_top?ie=UTF8

Initially when I plugged in the stick, nothing at all happened. I first followed this tutorial: https://blog.danielscrivano.com/installing-rtl8812au-on-linux-for-wireless-dual-band-usb-adapters/
After I did those steps, my wifi card did work as it should. I could utilize the 5 ghz band and had blazing internet speeds. When I shut down the computer and turned it back on, the wifi stick no longer works. It's like Ubuntu doesn't even recognize it is plugged in (no lights on the stick, if I search for it, I cannot find it). After that happened, I tried various other online tutorials/fixes and nothing worked; this usb stick seems permanently disappeared.

I wish I had bookmarked everything I tried, but didn't and don't remember all that I have tried (so sorry :() But I fear that I have made 1 royal mess trying to get this thing installed.

As I said at the beginning, I am a Ubuntu noob and you will need to provide me with your 'dumbest' advice.

Thank you so much