If you are adding trim to other parts of the door cut those pieces out as well.
How to install trim around a garage door opening.
Measure the inside dimensions of the garage door jamb horizontally across the top and vertically along both sides.
Lift up the trim and place it at the location you want.
Check existing rough opening for proper height width and plumb.
This will determine how long your trim will need to be.
You will need to measure both the height and the width of the garage door.
Use a hack saw to cut the trim to the length you need.
Step 3 position the weather stripping and trim above the garage.
Step 4 placing the trim to the sides of the garage.
Cut pieces of vinyl jamb material starting with the top jamb to match these.
Hammer the trim with the finishing nails and to get the best results ensure that the nails are approximately a foot away and the rubber edge is slightly attached to the garage door.