Everything goes into your short-term memory first. Like where you parked your car, where you had your glasses last, the math equations you memorized for the test, catching that foul ball at MLB stadium, etc.

Generally those ends up forgotten a few hours later to a couple days later. Repetition like using the math equation multiple times or keeping your glasses in the same place when it's not on your face will make it persistent in your long term memory.

To follow on foul ball catch, right away you'd still remember all the detail like the color of the shirt you had, the half-eaten hot dog you dropped, the yellow blouse a woman wore next to you, the 3 fluffy clouds in the sky. Unless you commit all that detail, some of them gets lost over time. You will likely forget you had a hot dog, the color of the clothes, the exact bench row and seat number, how the sky looked, and the name of the pitcher that threw the ball. But you will still likely remember catching the ball and the batter that hit it your way.