Well, it IS true. Try using a "gaming" keyboard for more than a hour or two without a break and your hands will be so sore you have to stop, something that doesn't happen on ergonomic ones. Also, "gaming" keyboards are ridiculously loud and clicky unless you get brown caps. Do a test by yourself, as someone who spends over half a day on a computer every day all year round, I tell you, ergonomic ones are the best, all you sacrifice are literally the stupid macros that "gaming" ones have, but those aren't even useful.
No need really, when you buy the parts, the motherboard will come with complete instructions on where even the smallest of screws go and so will the PSU manual!
Unity is a GREAT place to start! ANY "what you see is what you get" program is great to start, since rather than having to already know how to code, you can make something and at the same time be able to look at how the code changes with every edit. That way, you learn how to code and do each thing! It's a hands-on approach and it works wonders! I started using making games when I was 8, started with RPG Maker, learned Ruby from it, then moved to others and now I can understand and use almost any programing language in existence (not counting small ones like Brainfuck) and all game making software, so again, doing it like that is great for starters to learn how a certain language works.