During Viduy, one stands without leaning on anything and bows forward slightly (similar to Modim).
One beats his chest with his fist when he says each word of Ashamnu, at each Al Cheit on the word Shechatanu (and Al Chataim on the words Sheanu Chayavim), and at the words Slach Lanu, Mechal Lanu, Kapper Lanu.
[The word is enunciated with the sounded after the last vowel, i.e. Eloi-ah.]
When reciting Viduy in the quiet Amidah, one responds as he normally would in Elokai Netzor. [I.e. If the Chazzan recites Kedushah, one responds Kadosh, Baruch and Yimloch. When the Chazzan says Hamelech Hakadosh and Shomea Tefillah, one answers Amen. When the Chazzan says Modim, one answers the three words Modim Anachnu Lach. When the Chazzan recites Kaddish, one answers Amen Y’hei etc, and Amen to D’Amiran B’Almah.]
If one forgot Viduy in the Amidah, he should recite it afterwards.
One who is not davening with a Minyan, or at all (due to illness), should still recite Viduy throughout Yom Kippur the same number of times as it is recited in Shul. This applies to women as well.
It is advised to repeat the Confession at each point, as if he was in shul.
