Procedure in an experiment describes the steps to be taken to complete the experiment.
It makes note of what data should be recorded (color changes, gas escaping from a liquid, a precipitate being formed -- these sound like observations and they are, but the procedure makes sure you know that you should be looking for such changes).
It makes note of the order that the experiment is to be done. You don't want to do something out of order.
It tells you when to put ingredients into the experiment.