Panasonic KX-P8410 Operating Instructions Manual page 24

Setup
24
4
Insert the toner cartridge in the appropriately labeled slot.
From top to bottom, the order of the color toner cartridges is BLACK, CYAN,
MAGENTA, YELLOW.
5
Repeat steps 1, 2 and 4 for each toner cartridge.
When you have installed all the toner cartridges, go to step 6.
6
Close the right side door.