I had the hardest time understanding how to tuck one side into the other. It would not register how to do that. I hope I'm not the only one that had a problem understanding how to do it. :? So with high hopes someone may need more info on how to tuck and where to tuck: Open the rectangle by separating the two sides by pulling them apart from each other then tuck the top part of the fabric down into the bottom part. Finagle it to fit and smooth it out. :D :D