The pictures and instructions above are very good, but I found my model was slightly different, and others might find the same.
I took quite a lot of pictures but I thinl I'm limited to posting only 3
Wedge the spring open using pennies. Using 63 cents worth of pennies to wedge then into the spring open so it easily attaches to the cable tie. - Do this by wedging one penny into each turn of the spring, then replace those pennies with a stack of 2 pennies, then go and replace most of those with a stack of three pennies. This is sufficient to stretch the spring out so that no tension is required to connect both ends of the cable together. Note: The spring will curl into a "C" shape as it is wedged with the pennies, but it is still very pliable and easy to install this way.