Step 3. Verify Hinge can travel freely with no restriction. Also verify you have enough travel to open your door. On most offset hinge brands, you should easily be able to get 90 degrees or more of rotation.
When you are happy with the hinge movement, glue it to the fuselage with epoxy and milled fibers. 5 minute Epoxy is ok.

Note: the key to good bonding is SURFACE PREPARATION. I scuff the fuselage area where the hinge will be glued, and the hinge base with 120 grit sandpaper. Then wipe down both faying surfaces with acetone. Use a thick drop of epoxy, enough to squeeze out. Then use your finger to create a nice fillet all around. If you have C-clamps, clamp the hinge to the fuselage.