To frame in the doorway, it is fairly simple. The door itself acts like a big window opening once you tear out all the old door material. Other than the typical materila like wood, nails, screws, insultaion, siding (outside) and drywall, you’ll need some concrete anchors for the base plate to make sure the wall is secured to the foundation. The framing on the outside of the existing door should already be capable of holding the weight, so all you need to do is fill in the extising opening with similar materials.