Sometimes the parts list pics - which I think you already have - can help.
Otherwise the best way is as dave says ^^^.
As you take each item off either draw a sketch or take a photo showing it before removal. Lay out the old ones in the same positions as they were in when fitted. I do that a lot. (Be careful not to kick the layout
When removing numbers of bolts - such as those holding on casings, covers or cylinder heads - I draw a diagram of the part on cardboard & then put the bolts into holes punched with a screwdriver on the correct part of the diagram as I remove them. You can do the same with nuts & washers, just use sticky tape to hold them to the card. Old cardboard boxes are ideal.
Be especially careful with seals as they often need to be fitted a specific way round to work.