Unplug the odor eliminator from the outlet.
Pull the plastic grill forward with one hand, while holding the back of the odor eliminator with your other hand to remove the grill. The top of the grill should come open first with a small snap.
Pull out the used filter from inside the grill.
Remove the replacement filter from its plastic bag and press it into place inside the odor eliminator.
Place the grill back onto the odor eliminator. Slide the bottom of the grill into place first, then press the top of it in place until it snaps shut.
Turn the filter replacement indicator dial on top of the odor eliminator until it is one month ahead of the current month.
Plug the odor eliminator into the outlet.