Learning begins where pretending to know finally ends.

As long as you are performing understanding, you cannot receive any. The performance takes up the space where learning would happen, and it has to be maintained, which means the gap can never be addressed. Everything useful starts at the point where you admit the gap exists.

Find one area where you have been nodding along. Say plainly, to yourself first and then to someone, that you do not understand it. It feels like a loss of standing for a moment and it is the only door in. What follows is usually easier and faster than the years of pretending were.