csoundObj.sendScore(String.format("i1.%d 0 -2 %d", id, id));

I am looking at the MultiTouch example from the Csound android app.  What does this type of score line mean?

i1.3 0 -2 3 for example.

I don't understand "p1" and "p3" here. p1 is instrument but 1.3? and -2 for the duration?