Open the front cover of the Brother printer
Remove the drum unit and toner cartridge assembly
Press the lock lever to release the old toner cartridge from the drum unit
Take the new toner cartridge out of its packaging
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 into the drum unit until it clicks into place
Clean the corona wire by sliding the green tab left and right several times
Reinstall the drum unit and toner cartridge assembly into the printer
Close the front cover
Reset the toner counter if required by your model