Take the end of the rope in your right hand. Make a small loop in the rope with your left hand so the rope passes over itself (an overhand loop).
Feed the end of the rope through the loop with your right hand. Wrap the end around the main part of the rope from right to left passing the end behind the main part of the rope and back down through the loop.
Create a large loop between the small loop and the end of the rope. This will be your anchor point for the bridge. Pull the knot tight. Alternatively the anchor loop can be wrapped around an anchor point instead of creating a free loop.
Grip the middle of the rope and face the anchor point for the bridge. Hold the end of the rope that goes to the anchor in your left hand and the other end in your right hand.
Loop the rope three times around your left hand for a total loop amount of about 12 inches. With your right hand grab the middle loop and place it over the loop closest to your arm.
Grab the new middle and place it over the loop closest to your fingertips. Then grab the new middle rope and place it over the loop closest to your arm.
Grip the new middle rope and pull it through the other loops. Remove your left hand and pull. Attach D-rings as necessary for your bridge construction to your wireman's knot before fully tightening.
Wrap the rope twice around the anchor point.
Lift the end of the rope over the long section of the rope then feed it back under the long section. Pull the hitch tight.
Repeat the process for a double half-hitch which will provide a secure anchor point for a rope bridge.