Canon 3749B002 On-Screen Manual page 47

Note
The Film Strip Frame is not necessary for mounting the mount films. Be sure to remove the Film
Strip Frame.
3.
Load the Film Guide to fit in the grooves on the right and left sides of the Platen
Glass.
4.
Mount the mount films in the Film Guide.
TURN OVER THE MOUNT FILMS (with the correct image facing down) so that THE IMAGES WILL BE UPSIDE
DOWN, and mount the mount films in the film order FROM LEFT TO RIGHT.
Be sure to load the mount films properly in close contact with the Platen Glass.