The point of this exercise is to start simple. Begin with only two notes, the best choice is to use octaves (in this exercise, octave A's). Set a metronome to a certain tempo (it doesn't have to be 120) and start playing! See how many different patterns you can find just using two notes. In this exercise, I play a complete pattern in one measure and then repeat that pattern in the next measure. I then find a different pattern to play in the third measure, and then I repeat it, and so on.
Try out my patterns, then create some on your own. Concentrate on continuous playing; do not stop to think up a new pattern, just play what you feel. There are so many different choices, even with two notes. The really interesting thing to me is that it is possible to imply so many different kinds of music with just two notes. Close your eyes and listen to my example. When you begin to play, start slow and as you feel more comfortable, gradually increase the tempo.