Building a Police Box a.k.a. The Doctor's TARDIS
Step 14. Final touches (almost)
Add a door-stop around the door opening and a threshold piece on the floor that the door will close into. This is to stop rain blowing or running
in. Fix (approximately) 25 mm x 25 mm (1" x 1") wood up the hinged side of the door opening frame and
25 mm x 50 mm (1" x 2") stock to the other side.
Use 19 mm x 50 mm (¾" x 2") for the threshold piece. This is to stop rain-water blowing in and to give the door something to close against.
You can probably get all of the above pieces from project off-cuts.
Once the door-stops are in place, add a door handle and lock-set of choice.