Canon iR3245 Manual page 550

Press [2-Sided Original] to scan two-sided originals → select the type of
2-sided originals.
Press [2-Sided Copy] to make two-sided copies → select the type of two-sided
orientation.
Press [Paper Select] → select the paper source.
3. Press [Done].
7
7-82 Reducing Two, Four, or Eight Originals to Fit on a Single Copy Sheet (Image Combination)