Ok, here we go, Door Cylinder installation.

#1 install the air cylinder to the door. The location of the sylinder mount on the door may take some trial and error, as it will define the amount of available "throw" for the door....similar to installing a control horn. On an F-16, it will have to be on the lower 20% of the door, mostly to keep it away from the wheel in the retracted position.
Retract the cylinder, and tape the door shut to the fuselage.