Canon SELPHY ES2 - Manual (Page 18)

Preparing/Replacing the Cartridge
18 Getting Started
3
Grasp the cleaner unit that is inside and remove it.
4
Make sure that the cartridge is oriented as shown on the direction
indicator on the inside of the printer, and insert the cartridge until it
clicks into place.
5
Press the area marked PUSH to close the cover.
Protective paper
Direction
indicator