I would not use her directions for the roof section and instead use this method to make flying geese:
https://www.thesprucecrafts.com/flyi...ptions-2821434 There is a link to the tutorial on how to make them but this site gives the sizes you need to cut the fabric. Because the flying geese are twice as wide as tall, you may have to sew another rectangular section above the door, if you don't want the roof to end equal to the height of the door. But with this method there is no waste, and you get four identical roofs at once.
Hope this helps.