Yoma, Chapter 3, Mishnah 8. Once the Kohen Gadol is dressed in the four white garments in which he performs the service of Yom Kippur, he approaches the first of his offerings - the bull that the Torah commands him to bring for himself and for his household, which serves as atonement for him and for the members of his household. Of this the Mishnah says: "ba lo etzel paro" - he comes to his bull.
Where the bull stood:
"u'faro hayah omed bein ha'ulam v'lamizbe'ach, rosho la'darom u'fanav la'ma'arav" - the bull stood between the Ulam, the porch in front of the Sanctuary, and the altar. Its body was positioned so that its head faced south, and the head itself was turned toward the west, in the direction of the Sanctuary.
What is the reason for positioning it this way? Seemingly it would have been fitting for the entire animal to face the Sanctuary, but there is a concern that it may drop dung, and if its hindquarters were directed toward the altar that would be a lack of honor for the altar. Therefore it is positioned with its hindquarters facing north, toward the wall, and only its head is turned toward the Sanctuary in the west.
The semichah and the confession:
"v'ha'kohen omed ba'mizrach u'fanav la'ma'arav" - the Kohen Gadol stands to the east of the animal, facing west. "v'samach shtei yadav alav" - he places both his hands on the bull, and this is the procedure called semichah, which is done with all his strength. And while performing the semichah - "u'misvadeh" - he recites a confession.
And this is what he says - the text of the confession:
"Ana Hashem" - please, Hashem.
"aviti, pashati, chatati lefanecha" - expressions indicating that he has sinned against Hashem.
"ani u'veisi" - I and the members of my household.
"Ana Hashem, kaper na la'avonos v'la'peshaim v'la'chataim she'aviti v'she'pashati v'she'chatati lefanecha ani u'veisi" - a request for atonement for the sins that he and the members of his household have committed.
"ka'kasuv b'Toras Moshe avdecha: ki va'yom ha'zeh yechaper aleichem l'taher eschem mi'kol chatoseichem lifnei Hashem tit'haru" - that on this day Hashem atones for all sins.
The response of the people:
"v'hen onin acharav" - those standing around him, who hear the Name of Hashem pronounced by him, respond after him. The Name that the Kohen Gadol uses is the Shem HaMeforash, the four letter Name of Hashem, and upon hearing it they respond.
The order of the sins in the confession:
The order of the sins mentioned three times in this confession is the subject of a dispute, and as a matter of halachah we rule in accordance with the Sages, that one does not say it in this order but rather places "chatati" first, according to the ranking of the severity of the transgressions:
"chatati" - a transgression committed unintentionally, without intent.
"aviti" - a transgression committed deliberately, with intent.
"pashati" - a transgression committed out of a sense of rebellion, Heaven forbid.
In summary: In this Mishnah we learned about the Kohen Gadol's approach to his bull: the place where the bull stood, between the Ulam and the altar, its head to the south and its face to the west out of honor for the altar; the Kohen standing to the east facing west; the semichah with both hands and with all his strength; the text of the confession for himself and for his household using the Shem HaMeforash; the people responding after him; and the order of the three terms for sin - a sin committed unintentionally, an iniquity committed deliberately, and a transgression committed in rebellion.