American flag puzzle from postage stamps

After watching different series on TV for the last year, waiting on my disability, I decided to do some puzzles. My husband is a postmaster for 3 offices, so decided to do one for each of his offices….. 1000 piece puzzles, 20″ x 27″….. never mounted a puzzle before, first one, it kind of warped on me?!?! Hopefully I can straighten it out when I have a frame put on it…