First I used the window to create a cardboard template. It seems like the windows should come with templates, but they did not.
1. Put the template on the inside
of the van and line it up with the structural metal "cutouts". I taped the template in place then drilled three randomly located holes through the template and out through the wall of the van.
2. Put the template on the outside of the van using the 3 random holes as "registration marks"
3. Trace the template with a marker.
4. Remove template, cover outline with masking tape, put template back on and trace again this time onto the masking tape. The tape will help keep the paint from chipping around the cut.
5. Take a deep breath. Take a leak. Are you sure you want to do this? Using a jig saw with a fine tooth (24) metal blade at full rpms slowly cut out the van window opening.
6. I had a friend hold the steel cutout while I sawed the last inch at the top, so the cutout wouldn't fall onto the new vinyl floor inside the van.
7. Test fit the interior trim ring. It slides in between the exterior van wall and the interior structural van wall. The trim ring is split at the bottom to facilitate this process. One of my bottom corners needs trimming to allow the ring to fit completely. Right now the ring ends overlap eachother by a 1/4" to 3/8".
8. Lunch break.