Smoke signals weren't used as much by the Indians as people think. Some Indians used smoke signals, especially in the plains or in the southwest, where the sky is usually clear and the smoke signals can be viewed from far. They were very basic, though.

One short puff indicated the presence of an enemy group. If the signals were quickly repeated, it was a sign that the enemy was numerous and well armed.
A continuous, steady smoke signalled the Indians to rendez-vous at a certain point.