Open the front cover of the Brother printer
Remove the drum unit and toner cartridge assembly
Press the green lock lever and remove the old toner cartridge from the drum unit
Unpack the new toner cartridge
Gently shake the new toner cartridge side to side several times
Remove the protective cover from the new toner cartridge
Insert the new toner cartridge firmly into the drum unit until it clicks into place
Clean the corona wire inside the drum unit by sliding the green tab from left to right and back to the home position
Reinstall the drum unit and toner cartridge assembly into the printer
Close the front cover
Reset the toner counter if your Brother model requires it