Manual Tying Tool
Wrap the wire around the two pieces of rebar and cut it, leaving about 2 inches of extra wire on either end of the bar.
Grab the ends of the wire with the twister rotary tool's jaws and pull its handle. The handle extends out and twists the wire. (The same task can also be accomplished with a set of pliers, but the wire will have to be twisted by hand.)
Tighten the wire until it is snug.
Automatic Rebar Tying Tool
Adjust the torque dial on the tool to "0."
Turn the power switch to "on." Once the tool is turned on, do not place your hand near its rotating part.
Hold the tool at 45 degrees to the two perpendicular sections of rebar and place its "C" clamp around both bars.
Press the tool's trigger and hold it. The automatic rebar tying machine forces a wire around both bars, cuts it and twists it. Release the trigger after the twisting is finished. If the wire is too loose, increase the torque dial setting.