To wear this Tilly Dress, simply put it on like you would any other dress. When you notice the missing button, use the spare one. You can sew it on easily with a needle and thread. As for care, it's best to follow the general washing instructions for dresses. Wash it in cold water and let it air dry. Don't forget that this is a sample, so handle it with a bit of extra care to keep it looking great for a long time.