I'm definitely not an expert and there are plenty of good tutorials on this Forum about opening doors, but I will be glad to tell you how I did it. First: I take the tip of the back side (opposite of the cutting edge) of a X-acto knife and follow the gap around the door until it works its way all the way through. The corners sometimes take more effort. You'll be surprised at how clean this method cuts. After sanding the door and the jam I added trim inside the cab for the door to rest against. There are many choices for the hinge itself, but on this particular build, I used two dollhouse piano hinges on each door with plastic rod notched to look like hinge, filling in the gap between them. Next: the interior is somewhat of a challenge. Interior buckets generally taper at the bottom leaving a large gap. On this build, I gave the bucket a toss, and I made a new floor pan and with this being a short hood I made a dog house as well. This kit also had a glass bucket. I cut each individual windshield out of the glass bucket, used them, and threw the rest away. The dash had to modified as well as some other pieces, it is not perfect, but that is how I did it. I'm learning too, and I've found that the folks on this Forum are eager to help. I wont always open doors on every build, but I think it does add to the realism. Give it a try, you might be surprised how it turns out.