Programming is complex and simple at the same time. Simple in that there are enough books out there for anyone to read, learn all about it, to cheat off.
The hard part is the implementation of that program, the understanding of the movements and how they will react, how the stimulus you apply today will pay you back in weeks/months to come, but the same goes for the opposite effect. You can’t just pour volume/intensity and load into your program without consequence.
To be a great coach takes thousands of hours of watching, listening, learning and teaching. No shortcuts, just time and persistence. Anything worth doing takes effort and time.