The whole project took about 45 minutes one night while watching tv. (Sorry for the dark pics.) I first determined the size I needed my insert to be. Luckily for me the width was the same so I only had to measure and mark the length I needed my inserts to be.
Then I pinned the opening closed and hand stitched it together.
I took the remaining stuffing from the pillow inserts and used it to help fill the DIY Pouf I made. This quick project saved me a trip to the store and I was able to use the pillow inserts I already had on hand...woo hoo!