Lay one piece of rebar perpendicular across the second piece. Cut off a piece of wire from the spool if you are using pliers. Depending on the diameter of the rebar, the length typically ranges from 4 to 8 inches. Double the length if you plan to double the loops in the knot. Wire ties are precut and have a loop at each end.
Hold a piece of wire or a tie by one end. One inch from the end of the wire --- leaving a short tail --- lay the wire perpendicular across the top of the top rebar that runs perpendicular across the top of the other. The wire is parallel to the bottom rebar.
Secure the wire or tie it in place with the thumb of your weak hand, remembering the short tail. Pull the long end of the wire under the bottom rebar, bring it up on the other side and then half wrap it over the top rebar. Drop the wire back down under the bottom rebar on the opposite side of the first half wrap and bring it back up to the tail.
Twist both ends of the wire or tie them together by hand. Step on the rebar, grab the twist with your pliers and pull up or slide the rebar tie tool through both loops and pull up with the hook. Pulling up tightens the wire or tie around the rebars. Twist the pliers or tie tool to tightly secure the wire or tie. Wire has sharp ends. For safety's sake, bend the twist down parallel to the top rebar.