A reference design is exactly that: a design that can be used as a reference for building your own. Not mandatory design, nor for that matter a suggested design. The amateur radio station components listed here will provide you with a working station. I am purchasing these too, so that my tutorial and demonstration videos will use the reference station.
I’ve been asked many times, “What HF rig should I buy.” I used to answer, “Well, it depends.” No more. Now I say, “Buy what’s in the reference station: an Icom IC-7300.” I will try in every case to make a recommendation for something you can purchase, and minimize the number of things you must build.
Your circumstances will be different from mine. Perhaps you already have a radio in your station, and don’t want to change. No problem! Adapt the reference station to your needs. Note that my own station has capabilities, like a hex beam, that won’t be in the reference design. But the reference design can be a useful guide as you build out your station from the ground up, or if you’re upgrading it.