On the back side of your bag find the middle and place your button loop there measure over 2.5 inches and pin your handle raw edges together move 2.5 inches ion the other side and pin the other end of the handle make sure it is not twisted, on the front find the center and pin your handles the same way. I stitch across mine several times to secure them. Now put your pieces right sides together lining inside of the bag and sew around the top turn right side out through the hole in the lining bottom and top stitch around the top.
Hope this helps.