Once this is done, google the subject of the document. Most of the time an event worthy of an audio take will be visible somewhere as a text article or transcript. Check out your notes with this other source. You cannot be good at that immediately, but practice makes perfect as they say. Do it as often as possible. Results are spectacular.
Try first to absorb the document as sound only, during three successive runs, taking notes at all times, as described below, with different colors for each run. Make sure you leave spaces for the elements you fail to understand, so that during the next run you know where you need to be attentive, and you gradually fill out the blanks. You don't have to get every single word to understand the gist of the document
Audio documents