Begin by removing the two screws at the rear of each door.
Start at the rear and unsnap the top of the trim at the 5 fastening "straps". The trim needs to be pulled up and out to unsnap.
Here'* a closeup of one of the fasteners. The horizontal piece above the yellow arrow is what clips onto the trim:
Once you have the upper disconnected, pull the trim away from the door and locate the bottom fasteners. Use a wide screwdriver-like tool to pry at the red arrow below. The wider, the better cause you'll need to twist the tool with the limited amount of space between the door and trim.
This will give you a good idea of what remains on the car versus what is attached to the trim. Note the front most fastener. It'* a little different but releases the same way.
I've had pretty good luck removing the trim without any fastener breakage but use some care. I would think that they would be pretty easy to come by though in the event of damage.
EDIT: Welp, I guess I should have consulted the book prior to typing this all up. You'll notice that the above pics are from an SE. I was under the impression that SSE/i was the same but there are different procedures.
The screws are in the same place but the book says to start at the bottom edge (carefully pry outward) rather than the top. Then carefully pry center moulding
to disengage the upper clips. This is the black strip at the top of the trim.
Sorry for the confusion.