Most PC building these days is slotting components together and making sure nothing is stomping on something else's space requirements. There's some cable management and some applications of screws, pipes, and paste, but for the most part, PC component manufacturers are doing their best to make their components eminently and easily swappable. With, perhaps, the exception of the power supply and the case.

For people who are interested, I would recommend building a desktop computer as a learning experience. Not so much a laptop, portable, or miniature PC, as those are often designed in a way that maximizes the use of space and prevents a lot of those swapping capabilities, but full-size desktops are still eminently buildable, even by people who haven't done it before.