Normally, you sew with a 'baggy bottom' in other words, the longer piece is on the bottom and the feed dogs will handle the extra fabric. This works with short pieces of fabric and is difficult if the bottom piece has a seam. If you need to ease a top & a border, you need to pin along the entire length. The baggy bottom trick isn't going to work.
To ease, you find the center of both the border and the top & pin the ends, and the center. Next, find the center of the piece between the center pin & the end of both the top & border. Match this up and pin and do the same with the other side. Continue finding & pinning the centers until all the fullness is eased in.