Measure off and cut a 78" length of fencing to end up with a 60"x78" piece (Image 1). Make the cuts at the ends of the squares (Image 2) so you'll have several extra inches of wire to use as a handle to close the cage.
To create the cage, lay the fencing out on the ground and roll it up into a circle or column. Next take a short, narrow piece of pipe and use it as a handle to loop each wire over and through the wire squares on the other side. The pipe gives you leverage to bend the heavy wire, and it protects your hands from any sharp points.
To anchor the cage into the ground, weave a wooden stake through the wires (Image 1) and hammer it into the ground (Image 2). If you don't have a wooden stake, use a length of rebar, a PVC pipe or a metal pipe. Plant three or four tomato plants around the base of each cage. As the plants grow, you will need to tie them to the cage.