Parah, Chapter 3, Mishnah 8. This chapter walks us through the preparation of the Parah Adumah step by step, from the kohen's days of separation until the cow is burned. Our mishnah stands at the moment just before the burning: the elders take leave of the kohen with one final instruction, and the wood that will consume the cow is arranged in place.
The mishnah's words: "Samchu yedeihem alav", they leaned their hands upon him, "ve'amru lo", and this is what they told him: "Ishi Kohen Gadol, tvol achas", Master, Kohen Gadol, go down for a single immersion.
The ones who laid their hands upon him were the elders of Yisroel, and it was they who addressed him with these words and told him to go and immerse.
"Yarad ve'taval, ve'alah ve'nistapeg." He went down and immersed, and then came up and dried himself off with a towel.
A word about who this kohen is. Our mishnah presents him as the Kohen Gadol, and that is how the service was carried out here, but the preparation of the Parah Adumah did not require the Kohen Gadol; an ordinary kohen was also fit to perform it.
"Ve'eitzim hayu mesudarim sham: atzei arazim, va'aronim, uveroshim, ve'atzei te'eina chalaka." Wood was already arranged there: cedar wood, pine, spruce, and the wood of the smooth fig tree.
Why specifically these species? Because their wood is free of holes and knots, which makes it superior fuel and allows the fire to take hold cleanly and burn well.
"Ve'osin oso kemin migdal, umephat'chin bo chalonos." They would build the pile in the shape of a tower, and they would leave open spaces in it like windows.
The tower shape means that the pile was broad at its base and narrowed as it rose. The openings left in its sides served a practical purpose: air could enter through them and feed the flames, giving the fire its strength.
"Va'chaziso ma'arava." Its front side faced west, that is, toward the Sanctuary and toward the mizbe'ach.
So everything is now ready. The kohen has immersed and dried himself, the choicest woods stand arranged in a tower whose windows will draw in the air, and the whole structure is turned to face the direction of the Beis Hamikdash. The next stage of the service can begin.