New Exterior door and clapboard siding
Doors and windows always go first.
Then all the trim around the windows, soffits, then outside corners before the siding.
May want to do yourself a favor and remove that wood brick molding and replace it with vinly brick moulding. Wood brick molding will rot from the bottom up.
There should be flashing at the bottom of the rough opening for the door that gets installed before the door goes in. That will prevent water from getting in and rotting out the sub flooring.
There also should be some form of support under the doors threshold where it sticks out behond the sheathing. I use 1 X 6 vinyl lumber attached with stainless steel trim head screws.
Without the support the threshold will twist and crack the seals in the outside corners and will bend enough to crack the siding below.