Access to Air Filter; 91 Camry

You are pretty much there. After releasing the 4 clamps, gently pull the top half of the air box off. It won't come completely off, because it is still connected to the intake boot & such, but you will be able to open it far enough to pull out the filter element. And take care that none of the vacuum hoses from the air box come loose during the procedure.

See if you can find a Haynes repair manual. They're inexpensive and will guide you through that and other maintenance procedures with photographs and text. That was one of the first things I did after purchasing my Camry. Discovered a really poor quality filter element that looked like it was made of notebook paper (from quick lube place?) Next was searching for the PCV valve location, according to the Haynes book, just to familiarize myself with its location, and discovered a small leak in the upper radiator tank, so I was able to replace it before any real damage occurred. Always a good idea to familiarize yourself with under hood components if you have the interest. By this process I later discovered someone had neglected to replace the intake air temperature sensor in the air filter enclosure, leaving a hole for unfiltered air to enter.