1) If you don't have the finger strength to spread the Hip-Clip apart enough to get it around the small part of the shovel's shaft, use something like a large screw driver to pry it apart.
2) Use a pair of pliers to squeeze the clamp back together once you have it around the shovel's shaft.
3) You'll notice that one side of the clamp (where the bolt holes are) is bent at slightly more of an agle than the other side. Put the nut on the side with the least bend (see picture below). It was designed this way so that the side with the more extreme bend will help hold the bolt in place while the side with the least bend will give you a little extra room to spin the nut.
4) Tighten the clamp down snug onto the shovel's shaft so that it can't be moved by hand. Do not over tighten.