Figured It Out
I found the hidden catches. Facing the AC, after removing the cover and filter and taking out the four screws, look inside the right side frame and there are two plastic latches. Push hard with something on the bottom one and it should pop out of its hole. you can then slide a screwdriver on the outside of the frame and pry the upper one off. Then pull the frame out while lifting to get out of the top latches and slide the frame to your left to free the other side. Then cleaning the mold is a whole other bear!