Yoma 3:5-6

Yoma 3:5

The morning incense was offered in between the head and the limbs of the tamid offering. The afternoon incense was offered between the limbs of the afternoon tamid and its libations. If the Kohein Gadol was too old or weak to endure immersing in cold water, they would heat water for him and pour it into the mikvah to warm it up.

Yoma 3:6

They brought the Kohein Gadol to the chamber called the Beis Haparva, which was on holy ground. They hung a linen sheet between him and the people. He washed his hands and feet, then undressed; Rabbi Meir says he undressed first and then washed his hands and feet. He immersed, came out and dried himself. They brought him his white garments, which he put on, then he washed his hands and feet.