Canon MG8100 series On-Screen Manual page 87

Cassette.
Note
There may be a little space between the Paper Guide (A) and the paper stack.
(4) Slide the Paper Guide (B) on the left to align completely with the side of the
paper stack.
Note
Do not load sheets of paper higher than the Load Limit Mark (C).
Insert the Cassette into the machine.
(5)
Push the Cassette all the way into the machine.
3.
Open the Paper Output Tray gently, and open the Output Tray Extension.
Note
After loading paper
When using the machine to copy or print without a computer, select the size and type of the
loaded paper for Page size and Type on the print settings screen.
See
Changing the Settings
Changing the Settings
When printing with a computer, select the size and type of the loaded paper in Printer Paper
Size and Media Type in the printer driver.
Printing Documents
See
in "Printing Photos Saved on the Memory Card / USB Flash Drive" or
in "Making Copies".
.