This pattern is quite simple but if you have already learnt Mills Mess or Inverse Mess you will have a hard habit to break, so if you can do either of those two patterns you have a good reason for learning this one.
Start with all three balls, two in one hand & one in the other. Start with a cascade throw with the hand holding one ball, while the ball is in the air cross your empty hand over the hand holding two & catch the ball again. Now with your arms crossed, throw one of the balls in the hand that is holding two up Under the arm. When the under the arm throw peaks, throw the ball held in the arm on top straight up on the outside of the pattern, then uncross your arms & catch the under arm throw in your empty hand. As the outside ball peaks throw the second ball from the hand that held two as a cascade throw up through the centre of the pattern towards the other hand. Catch the outside ball in your now empty hand, then catch the cascade throw in the other so that you finish holding two in one hand & one in the other but the opposite way round to which you started.
There are only 4 throws in the sequence. You can pause for a think after the first throw & catch, only the last three require any 'actual juggling'. Once you complete all 4 throws & catches, do the same on the other side. Keep practising until you can perform the sequence on each side smoothly without stopping to think what comes next. Keep practising even more until you can blend the two sides together by making the first throw of the next sequence the moment you make the last catch of the last sequence.
Personally I'm happy to leave the pattern there but the 'true' Rolf's Wave is supposed to be done with a few Claw catches. So juggle the sequence again but this time claw every ball except the throw made by the hand on top when your arms are crossed over.
For a little more interest make the first throw of the sequence Behind the back or Over the shoulder, or always catch & throw the first & fourth throws (same ball) in a Fork, catching the first throw Penguin style looks nice as well.