If you go to pcpartpicker.com, you can select components and it only shows parts that are compatible with the parts you've already selected. It made selecting parts super easy. And I was shocked at how easy it was to build a PC. It only took maybe 90 minutes including 20 minutes skimming a YouTube video on how to assemble a PC. And installing Ubuntu was maybe 30 more minutes (15 minutes to make a bootable thumb drive and 15 minutes to install the OS on my new machine).
It was so much less of a hassle than I had expected.
That being said, I wouldn't make a PC until RAM and storage prices come back down to earth.