Reverse Engineering a PCB is a well known field (https://en.wikipedia.org/wiki/PCB_reverse_engineering); but you still have to have some knowledge of individual components, math, physics, and theory before you can get started with this.
There is plenty of material and videos on the web if you search for it; also a book The Art of PCB Reverse Engineering: Unraveling the Beauty of the Original Design by Ng Keng Tiong.
There is plenty of material and videos on the web if you search for it; also a book The Art of PCB Reverse Engineering: Unraveling the Beauty of the Original Design by Ng Keng Tiong.