Rosh Hashanah, Chapter 2, Mishnah 3. In the previous mishnah we learned about the torches that were waved to announce the sanctification of the new month, and now the mishnah describes how they were actually lit.
How did they light the torches?
They would bring materials that all burn extremely well:
Long poles of cedar wood - long beams that served as the base of the torch.
Reeds.
Balsam wood.
Tow of flax - the waste fibers beaten out of the flax.
All of these were tied together with a rope, and a person would carry them up to the top of the mountain and set them alight.
Once it was lit, he would wave the torch in two motions: "molich u'meivi, ma'aleh u'morid" - back and forth from side to side, and up and down, so that the light would be visible from far off and would be recognized as a deliberate signal rather than a chance fire.
And so he would stand and wave until he saw his counterpart doing the same on the top of the second mountain, and that man until he saw the third, and so on, in a single chain of mountains passing along the news.
In summary: in this mishnah we learned the procedure for lighting the torches - the flammable materials tied together with a cord, the ascent to the mountaintop and the lighting, the waving motions of "molich u'meivi, ma'aleh u'morid," and the ongoing relay of the signal from mountain to mountain until the information had spread everywhere.