Roll Down - Two Coin Splits
The easiest way to learn the full flourish is to break down the trick into smaller parts. Here are three easier sub tricks in which two coins are split out of a stack into an edgewise grip between adjacent pairs of fingers. For all these moves the hand should be held in front of you with the palm facing to the left (assuming your right handed). The outer coin of a stack is the one closer to the fingertips.
Index Split (541k)
Start	Hold a stack of two coins edgewise between the thumb and index finger. The linked video above shows all three Two Coin Split variations.
Directions	Bring the middle finger next to the thumb so that it is also holding onto the edge of the coins. Keep a firm grip on the outer coin between the middle and index fingers while the thumb pulls up on the inner coin and pulls it out of the stack. Straighten the middle finger and thumb to finish the split. The outer coin should now be held edgewise between the index and middle fingers while the inner coin is held between the thumb and index finger. Reverse the moves to roll the coins back into the original stack.
Comments	If you are having trouble pulling a coin of the stack in Step 2 take a look at the comments for the Coin Flip trick where some tips are given on this. For the initial grip on the stack make sure the coins are held against the index finger at the middle point of the second phalanx. It is easier to hold the coin edgewise at this position, and will become more important later on.
Middle Split
Start	Hold a stack of two coins edgewise between the thumb and the middle  finger.
Directions	Bring the ring and index fingers to hold the edges of the coins. The three fingers and thumb should be evenly spread around the stack. Bring the thumb down next to the ring finger and slightly pull up on the inner coin to seperate it from the stack. Press against the outer coin with the thumb so it is pushing both coins against the middle finger. At this point you should be able to release the grip with the index and ring fingers and be holding a slightly off center stack of two coins edgewise between the thumb and middle finger. Bring the ring finger to a position next to the thumb and push against the outer coin. At this point also bring the index finger to a position next to the middle finger. Pull the ring finger back so the outer coin rolls down out of the stack to be held edgewise between the ring and middle fingers. At the same time pull the inner coin away from the middle finger with the thumb and index finger and move it so that its bottom edge is against the top side of the middle finger. Release the grip with the thumb to finish the split. At this point the outer coin should be held edgewise between the ring and middle fingers and the inner coin is held edgewise between the index and middle fingers. Reverse the moves to get back to the original position.
Comments	This is slightly more complex than the Index Split.
Variations	Once you can do the middle split with two coins practice it with 4 coins. Treat the two outer coins as a single coin and the two inner coins as a single coin and perform the Middle Split as above to finish with two coins held edgewise between the middle and index fingers and two coins held between the middle and ring fingers. This move is important for learning the full Roll Down later on.
Ring Split
Start	Hold a stack of two coins edgewise between the thumb and the middle  finger.
Directions	Bring the ring finger next to the thumb. Release the grip with the thumb and pull down with the ring finger to hold the two coins edgewise between the middle and ring fingers. Bring the pinkie finger as close to the middle finger as possible and press into the stack of coins. Pull down with the pinkie finger and pull the inner coin out of the stack to finish the flourish with the outer coin held edgewise between the middle and ring fingers. Reverse the moves to get back to the original position.
Comments	Pulling the inner coin down out of the stack with the pinkie finger is the hard part of this move. At the same time you should also be pulling up with the middle finger on the outer coin to assist in the seperation of the coins. Slightly twisiting the coins can also help to get a better grip on an individual coin. Gripping the two coins too hard with the ring finger is another problem that might make it difficult to roll out one coin with the pinkie finger. Try relaxing the grip with the ring finger.