Here is a link to the different stages of mastering a skill.
To sum it up you are either you know or don’t know your skill level. You demonstrate your skills either consciously or unconsciously.
Walking or drinking from a glass of water can be a skill done unconsciously. You don’t have to consciously put one foot forward nor do you have to make sure you swallow the water instead of breathing it into your lungs.
It is the goal to reach an unconscious level of competence where you don’t have to think about drawing the gun, trigger press etc.