Upon entering the forest, Teddy will explain your new objective: finding the four memories. The first memory is typically found relatively early in the chapter. Follow the main path, using Teddy's light to illuminate your way. You'll encounter fallen logs and small inclines that require you to crawl or climb. Look for glowing, ethereal fragments; these are the memories you need to collect.
The first memory is often located near a distinctive landmark, such as a large, gnarled tree or a small, abandoned structure. When you approach a memory, you'll hear a distinct sound cue, and it will glow more brightly. Interact with it to collect it. Collecting a memory will trigger a short, often unsettling, flashback sequence, providing glimpses into your mother's past. These flashbacks are key to piecing together the game's narrative. After collecting the first memory, Teddy will guide you towards the next area.