Canon imageCLASS MF3010 VP Multifunction Monochrome Laser Printer - Manual (Page 210)

Fit the protrusions (A) on both sides of the toner cartridge into the guides located on both sides of the machine
and slide the toner cartridge into the machine until the toner cartridge comes to rest and is held against the
back of the machine.
8
Close the toner cover.
When you cannot close the toner cover
Make sure that the toner cartridge is properly set in the machine.
Do not try to forcefully close the toner cover, as this may damage the machine.
9
Lower the scanning platform.
Maintenance
205