Opening
The Web site needlepointers.com refers to the beginning of the Jacob's ladder trick as "opening A." Learning opening A creates a good foundation for learning multiple tricks as it has many uses.
Start with a length of string or rope 6 feet long. Tie the two ends together, so you have two sides measuring 3 feet each. Drape the string over your palms, with the string in between your pinky and ring finger and in between your thumb and index finger. This will have the string in front of your ring, middle and index fingers of each hand but behind the thumb and pinky of each hand.
Tuck the index finger of your right hand under the string on your left hand and pull to tighten. Do the same thing with the left index finger.
Jacob's ladder
Once you have the opening complete, move onto the actual string construction of Jacob's ladder. With the opening section pulled tight between your hands, release the strings from your thumbs. Move your thumbs downward under all of the strings, wrap the bottom string behind them and bring it back to the top. With that string securely in place, pass over the second string from your thumbs and under the third string, bringing that one behind your thumbs and to the top as well. Release the strings from your little fingers.
Move your pinkies over the first string from the bottom and under the second string from the bottom, wrapping that one around your pinkies and pulling it to the bottom of the design. Release all of the strings from your thumbs again; this forms a rather large bunch of strings in the center of the design.
Move your thumbs over the first two strings from the top, and wrap the third around them, returning it to the top of the design. With your right index finger and thumb, grab the string that is wrapped around your left index finger. Pull it so that it also stretches over your left thumb. Repeat with the string on your right hand.
Again with your right thumb and index finger, pick up the bottom loop from your thumb (not the one you just put there) and bring it up and over the top of the thumb, then release it. Repeat for the string on your right hand.
You will now see a small triangle formed in between your thumb and index finger on each hand. Pass your index fingers down through these triangles. With your fingers in these triangles, bring your hands closer together so the string goes limp. Drop the strings from your pinkies; only your index fingers and thumbs will be holding string. Rotate your hands away from you, so that your palms are facing the ground, and pull the string tight to reveal the Jacob's ladder.