When I take something apart, I use a piece of cardboard to help remember where everything went. For example, when removing the cylinder head, sketch the shape of a cylinder head on a piece of cardboard, punch holes in the cardboard with a phillips screwdriver approximately where the bolts are. Label the drawing front, head, valve cover etc. As I remove the bolts, I stick them into the cardboard. This helps me to remember what the bolts were for and where they went. The picture shows the six spark plugs I just took out and keeps them in order by cylinder, and another piece of cardboard with fasteners from a riding mower that is waiting for parts
I have used this technique for years. It has saved me many times.
Whenever I start working on a car with a person who is just starting out in this hobby I make them use this technique. I get some push back. They are pretty quiet when we start putting things back together in 3 or 4 weeks. What they thought was obvious when we took it apart is no longer obvious.
The funniest story about this technique happened when 2 people I had worked with met each other for the first time. They determined that they both knew me. They immediately asked each other if I made them use the cardboard fastener holder.