My father taught me and my brother to build computers, like, 20 years ago, but the one thing I never liked doing (and that he always did) was the CPU. Everything else we were able to do ourselves.
When I upgraded my computer these past months, it probably had been 10 years since I last did it myself, and I found myself silly when it took me 3 times to properly plug the GC (one retry because I failed to remove all the rubbers from the pins, and a second one because I forgot to plug the supply

), but that's pretty much the worst I got (that and a slightly capricious RAM stick) so it felt like there wasn't much to worry.
Patience and care are key, going one step at a time while keeping a pragmatic mind.
But if you bought a pre-built PC, it means that at worst, you'll have a map to know what goes where if a component needs to be upgraded for something a bit stronger.