Disconnect power to the microwave by unplugging it from the wall, or by turning off the breaker in your fuse box.
Remove the two screws, located on both sides of the grill at the top of the microwave, then remove the grill.
Slide the old filter toward the front of the microwave to remove it. The filter, which is located in the center of the compartment behind the grill, is flat and has a metallic edge.
Remove the packaging from the new filter, then insert it into the filter slot.
Replace the grill, then secure it using the two original screws that were removed.
Restore power to the microwave to complete the installation.