You must collect all amulets (like Timmy's Ball) and aconite plants to progress the story and reach the final encounter.
Use your flashlight to navigate dark corridors, but remember to look for the Monocle early on; it reveals hidden paths, such as ladders or markings, that are invisible to the naked eye. Key Story Items & Puzzles
If you are being chased or hear her coming, hide inside closets immediately. Wait until the music stops before coming back out.
When you hear unsettling music start to play, it means the Mother is nearby.
For detailed visual help, you can check the Silver Chains Full Walkthrough or the text-based Achievement Guide on Steam.