I initially really dug the style this is in. However, upon reading the content I have begun to question it:
For Research & Concept:
"This is the time when the big requirements are agreed upon and a direction is chosen. This is also the moment when the initial idea is developed into a basic draft/prototype."
Two things: 1) I believe they have missed an entire step of the design process: research & discovery. This is qualitative research (not anecdotes, which many mistake for qualitative study) used to explore the problem space (the issues customers are facing—and how frequent and severe). You can bring hypothesis' to bear (we're humans) but this isn't the time to choose yet. That's product strategy.
2) There is research at the beginning of the design-solution development process and I think this is what they mean by Research & Concept (usability, learnability, heuristic evaluation, taxonomy, discovery benchmarking, etc.) but I feel this guide for "the pros" neglects to explore 1/4 to 1/2 of the design process based on the double diamond "building the right thing" and "building the thing right" standard.
It is a website, not a book.