Mike,
Twist the handle 180 degrees. When installed, there is a flat tab sticking straight up that holds everything together.
If it has had some use, you may need to press a flat head screwdriver on the tab to get it to spin. In that case, you would have to move the ring that holds the bucket.
Let me know if it doesn't work, I may still have the installation instructions at home I could scan you to get you pictures.