I would have to agree with Joe the Plumber. The fact that you dont know how to build a pc from scratch doesnt mean that you should feign ignorance in order to give extra $$ to a company to custom build it for you (especially when they only place a 1 year warranty on all parts, just so that theyll get you to pay extra $$ for additional year(s) warranty).
Heck, if you research power supplies carefully, some come automatically with a 5 year warranty (thats why I chose mine) & you dont have to pay any extra $$ for the extra warranty. But I will also agree that when it comes to watching the videos, dont rush the process by any means. Take as much time as you need & if this involves taking multiple breaks, so be it. The 2-3 hour time table is about avg, which means that you shouldnt put that # into your head. Never hinder yourself on a certain amount of time. The most important thing about these parts is the fact that you get them installed correctly, not simply trying to install them as fast as possible so that you can get to gaming asap.
However I will give 1 simple piece of advice: give yourself some extra patience when it comes to the cpu. Depending on which cpu you purchase will depend on how easy or hard it will be to install the heatsink fan. It sounds like based on your price range that you might be interested in getting an aftermarket heatsink in order to overclock the cpu. If this is the case, then first go search up a video on how to install the specific aftermarket heatsink & again take your time when it comes to installing it because not all aftermarket heatsinks install the same way. Also make sure to get yourself some silicon paste (I choose Arctic Silver 5, but ive heard of other companies who are just as good).
I hope this info helps you out OP.