Removing a Hasselblad 80 CF focusing ring

So I got a 51700 focussing handle for my 80 CF lens, but I'm not sure how to install it. I've read I need to remove the focusing ring already on the camera, but I'm not sure what the best way to go about doing so. I just want to do it right so I don't accidentally end up breaking the original ring.

I believe you need to slide the rubber ring toward the back of the lens to get it off... but I've never done it myself so I can't tell you how easy/difficult that is.

The ring snaps on and off, there are a few points which hold it on. They do have a tendency to break though so go easy.

Mine slid off by inadvertance... So it's pretty easy.