Well, articles about touching said hardware directly is exactly I'm missing here. As far as I can see, the only article about actual code is article 5, and that one is about "using EFI’s Simple File Protocol to read and write files". That doesn't qualify as bare-metal programming to me. Perhaps the goal is for those articles to appear later, but for now this is "prerequisites for doing bare-metal programming" more than "first steps".

Of course, I'm aware that doing actual hardware access on a complex platform such as x86 is massively complicated, which is why most bare-metal targets tend to use simpler platforms in the first place.