If you know that you don't know something, then you're already one step ahead of the game, because many programmers dive in thinking that they do understand som

If you know that you don't know something, then you're already one step ahead of the game, because many programmers dive in thinking that they do understand something and don't find out until it's too late that they never did. Deciphering large codebases takes a LONG time. Months often, to get up to speed. One thing that has always helped me is to take notes. Especially if you start getting lost in a deep set of function calls. Write all that down. Form hypotheses on what parts of the code are doing and try to come up with ways to test those hypotheses. Soon it will start to become less murky. It just takes a lot of time and perseverence, even for veterans.