I was not sure at first where the last bolt was. So I hope this helps.
I cut the “Cut here for service” plastic and then removed the blower resistor (3 screws). I could not get to the last bolt from that opening. I drilled a 3/8” hole 4 ˝” down in the A/C evaporator box. I used a 10mm socket with 3” extender in the opening (after I dropped it once I strapped a wire tie to it). I inserted another 6” extender outside through the hole into the 3" extender and went straight in to the bolt. This made things very easy for me. By the way I put a rubber plug back in the hole. I used a ˝”plug from ace hardware ($.25) with some RTV to keep it in place.