Insert a plastic card up into the corner of the air vent slot near the top of the rear case.

Push the card toward the top of the iMac to release the front bezel latch.

Pull the front bezel away from the rear case.

Repeat this process for the other side of the front bezel.

If the bezel refuses to release, try lifting the lower edge of the front bezel slightly away from the rear case (detailed in the next few steps) and repeat the latch release process.