#1 Always scan instructions in hi resolution - 300 dpi
#2 Resize all scans to resolutions between 2500-1900px in height
#3 If pages are in grayscale, convert them in some graphics program from RGB to grayscale mode
#4 Use levels option to create more contrast images to increase readability
#5 Use crop tool to remove all unwanted elements
#6 Create pdf file with all pages keeping numeric order
#7 Try to save files few times using normal mode, reduced size or optimization mode. Check which file has best balance between file size, quality, readability.
#8 If it's possible include box cover
#9 Upload them on server adding all necessary informations.
Thank you for your help.