The basic idea is to find those kuji-kiri meditation spots, which are scattered around different areas with one really close to the hideout waterfall. When you get to one, you'll need to nail the timing-based mini-game where the prompts fade in and out to match specific chimes, and getting the rhythm just right is crucial for unlocking the memories. What's interesting is that the button presses need to sync perfectly with the audio cues, otherwise you'll have to restart the sequence.

The order doesn't actually matter but you'll need to complete four different spots to see all the important backstory stuff. Each successful meditation, when timed correctly, gives you a knowledge point and triggers one of those memory sequences about naoe's past. Pay attention to the visual indicators during the mini-game, since they start fading faster as you progress through the sequence and the timing windows get a bit tighter. Good to know that if you mess up the rhythm, you can immediately try again without any penalty, just watch for that slight pause between the chimes that signals when to press.

These memories are pretty crucial since they're tied to the before the fall questline, and you won't be able to progress further in naoe's story without completing them, so it's worth taking the time to get the timing down pat.