Good tutorial for those looking to build their first PC. I would offer that everyone building or working on a PC should be able to afford a $7.00 anti-static wrist band. It can save them the cost of new RAM or similar so it's a one-time very small investment that will last them forever.
I'd also offer that there can be a lot of frustration trying to install some components or cables so builders need to allow plentry of time to take breaks to handle the frustrations that always occurs even for very experienced professionals.
It's worth noting that they sell screw starter tools with flexible wire fingers that make installing the mobo and similar screws way easier as these are small screws that are difficult to handle.
Intel designed the ATX cases with the PSU at the top of the case because heat rises and the PSU fan can easily extract it. Any quality PSU is not compromised by the typical heat generated in a PC. A quality PSU is a wonderful value when it has a 10+ year replacement warranty and provides optimum clean power to all of the components extending their life vs. a low quality PSU with dirty power.