If you go here:
You can download the operation manual for that machine, on page 4-5 they explain how to replace the toner and have pictures showing how.
here is the text on how to replace.
1 Open the front cover.
2 Pull down the toner hopper lock lever and pull the toner
hopper out slowly until it stops.
3 Tap on the top of the toner cartridge 5 times. Hold the
new toner cartridge vertically and vigorously shake it
up and down about 20 times, then invert the cartridge
and again shake it up and down about 20 times. This will
loosen the toner and allow it to flow more easily into the
4 Place the new toner cartridge with the tabs in the
notches as shown.
5 Slide the toner cartridge along the guides over the toner
6 Hold the toner cartridge with one hand while pulling on
the sealing tape to remove it.
7 Tap on the top of the toner cartridge 5 times to start the
flow of toner into the toner hopper.
l If the toner cartridge was sufficiently shaken as described in step
3, it will take about 50 seconds for the cartridge to empty. Do not
remove the cartridge until it is empty. If not empty, tap on the top
of the cartridge again until empty.
8 Slide the empty toner cartridge back along the guides
and remove it.
l The cartridge opening will be closed as it is moved back along
9 Slide the toner hopper into the copier and return the
toner hopper lock lever into place.
10 Close the front cover.
Add only one cartridge of toner.