I made this wreath a few years ago. It hangs year 'round on a door handle on our second floor. I made it by sewing vintage white buttons (some are fancy, some are plain shirt buttons) to white ribbon then wrapped the ribbon around a styrofoam wreath form. I tied a long piece of white ribbon around the wreath to form bow and hanger.
closer up view
You can get the styrofoam wreath form at craft stores like Michaels. Just pick the size you want your finished wreath to be. Warning - it takes more buttons and more time to sew than you would think! You might want to start small. My finished wreath is 9" in diameter and it is plenty large enough for hanging from a door handle. I had purchased a couple of large lots of white buttons on eBay and used those. You can buy buttons in bulk at craft stores but buying new buttons meant for garments would get a little expensive for this project.
If you want to try making your own button wreath and need more detailed directions, just leave a comment and I'll get back to you.