"When I am doing a frequent act, one for which I am quite experienced and skilled, most of these stages are subconscious. When I am still learning how to do it, determining the plan, specifying the sequence, and interpreting the result are conscious." (Norman, 2013 p. 40)
This reminds me of the exercise "How to Tie a Shoe". At my age, I have done this so much that I can do it with my eyes closed. However, explaining it to someone who has never done it before is quite different! We will find that we will leave out important information because so much of it has become subconscious in nature.