1) Attach the Rockit to your stroller. You will get the best rock with it mounted as high on the handle as possible.
2) Turn on with the button on top
3) Slowly change the speed until you notice the most rocking. It may not be the fastest speed - often you can get a nice rock at lower speeds if you hit the sweet spot (resonance frequency) of your particular stroller / pram.
4) Or you may just want to set to the speed your baby likes the most! If you do wish to have a lower intensity of rock you can either turn the speed down lower or mount the Rockit lower on the handle or tube of your stroller.