you see a drum unit in the package list but can't find it in the package, it might be because the drum unit is
preinstalled into your printer. Please refer to the following instruction on
how to remove the drum unit from your printer.
Step 1. Open the front cover.
Step 2. Remove the orange packing material.
Step 3. Take out the drum unit.
Please watch the video below for more information about setting up your Brother printer.