Turn off the Nature's air purifier and unplug it from its power source.
Locate the flat, filter plates at the back and inside of the unit. Grab each plate's handle and slide the filters from the air unit, one at a time. Slide the plates straight out from the unit. Some models have arrows printed on the edges instead of handles. Do not bend or twist the filters.
Unscrew the grill plate that covers the fan. Remove all four screws and set the screws aside so you don't lose them.