Yeah I Think I'm just stuck. Got the drive installed. Hooked the PC'a VGA cable up to a monitor, turn everything on. Inserted the thumb drive which supposedly has Windows 10's install on it.
Seems to boot up normal at first...
Whoa, new window just popped up called Windows Setup, holy [censored]. I swear this didn't happen before. Ten minutes ago there was a message saying "NO BOOT DRIVE OR HARD DISC FOUND' or some such. But now there's a window with several drop-down menus like...
Language to install: English (United States)
Time and currency Format: English (United States)
2Keyboard or input method: US, I guess. There's a bunch of options here. Fork it, let's try the Next button.
Windows
Install now
That's an onscreen button. Heck yea I'll install now.
Really, what happened in between my first try and this second one is I Google'd the error message which showed up ("no disc or boot drive...." and it suggested I turn off my computer, unplug its power, and then hold the power button for 15 seconds, so I did all that before plugging it back in And turning it on again.
"Setup is starting" it says. 'MICROSOFT SOFTWARE LICENSE TERMS" the next screen which POPS UP, like Jiv Hirtel in Hackdirt says, along with a bunch of legalese, which I scroll down taking a brief read here and there, pretending to understand what it's saying.

hee hee!
I accept the license terms, sure, why not? Let's press next.
Which type of Installation do you want? asks the next page with two buttons:
1). Upgrade: Install windows and keep files, settings, applications? --
What files, settings & applications? The SSD is supposed to be blank, so I'll choose the next option, which
2). is "Custom: Install Windows only (advanced) The files, settings, and applications aren't moved with this option....blABLABLA" okay, sounds about right. I select this second option.
Weird. Where do you want to install Windows? it asks, and it's showing a picture of two discs. The old HDD IS still in there, but I swear I disconnected it.

Dangit I gotta look into this. BRB.
Alright I'm back. Apparently I had a second thumb drive hooked up. Removed it. Back in business now. "Let's add your account" this new page says. Cool it just found our wifi and I just made a PIN number.
"Always have access to your recent browsing data? Hmm, Not now I choose. Not a fan of having my devices all 'synched up'.
"WE'RE GETTING EVERYTHING READY FOR YOU, This may take several minutes...." Heck yea!!!
Holy [censored] I got a desktop, whoa!!! Let's try installing Elder Scrolls Arena!
See y'all later.