Clean OS install

[Gracin]

When I built my pc 4/5 years ago, it was the first I built and the first time having one with an SSD. I wasn't aware that I could install the portions of Windows onto the SDD that would benefit from faster read/write speeds and then the remainder of windows be installed onto my HDD. At the time my budget allowed for a 128GB SSD and a 1TB HDD, which over the years I've managed to gather enough shit that I'm now running low on space. I've ordered me a 2TB HDD along with a 256GB SSD to add to my build, which will tide my space needs over until I decided to rip my movie collection at least.

I'd like to do move all my important files over to an external, and do a fresh install of windows. And this time do the portioning of the windows install, so as the 128 will now be a dedicated windows OS hard drive, but all program files, docs, pics, movies, music and such will be stored on the HDDs. And then I will use the new 256 for games that will benefit the speed.

Only issue is, I'm only computer handy enough to get myself into trouble. And tbh I'd rather not fuck this up. I haven't looked through my list to see what programs I will be moving/reinstalling when the fresh install in completed, but I doubt there will be very many. I'm just not wanting to lose any licensing for programs I've paid for, like Office for example.

If anyone knows a good guide I can follow to make this all go relatively smoothly. Or if you have some advice for an endeavor like this I would greatly appreciate it. I've googled how to do a clean install of windows, but none of the ones I looked over seem to cover the portioning of SSD/HDD.