Installing our Spartan Cab Doors is as simple as removing the plastic (molded) door and positioning the etched-metal door in place. Please see the photo and model by Joe Gartman:
I would recommend removing the molded door by drilling through the door in numerous spots with a roughly #70 drill, then using a sharp blade to connect those holes. Eventually you will be able to remove the material and clean-up the doorway. Then, you can paint the metal etching to match and affix the part with CA glue of your choice - we recommend anything 'medium' viscosity.
Please feel free to contact us with any additional questions. Thanks for the support!