No person may enter the Temple Courtyard for service, even if he is tahor, until he immerses himself [in a mikveh].  On this day, the Kohen Gadol immerses himself five times and washes [his hands and feet] ten times, all of them in the Holy atop the Parvah Chamber, except for this one only.

They spread a linen sheet between him and the people. He undressed, descended, immersed himself, ascended, and dried himself. They brought him golden vestments, and he donned them; then he washed his hands and feet. They brought him the daily offering. He made the incision and another completed the slaughter for him. He received the blood [in a vessel] and threw it.  He entered [the Temple] to burn the morning incense, and to prepare the lamps [of the Menorah]. He offered the head and the limbs, the chavitin meal offering and the wine.