Yizkor is recited before Musaf. Those who leave the Shul for Yizkor may recite Av Harachamim after Yizkor if they wish to. Yizkor does not need to be said with a minyan or with a Sefer Torah, and can therefore be recited at home too.
Ideally, Musaf should be davened before the earliest time for Mincha (12:58pm).
Since the Chazzan cannot move out of his place to bow at Aleinu and during the Avodah, he stands at a distance from the Shtender, to allow him space to bow unless someone moves the Shtender.
The paragraph of Misod (beginning of Chazarat Hashatz) is recited by the Chazzan and not the congregation.
One should stand for u’Netane Tokef.
According to the Chabad custom, the Chazzan recites the entire Aleinu – including the second half – out loud. The congregation quietly recites it word for word with him, bowing at V’Anachnu Korim, and continuing until Hu Elokenu Ein Od. At that point, they begin saying the Pesukim of Atah Harayta, as printed in the Machzor. The subsequent paragraph (beginning Achilah) is recited by the Chazzan only.
When one bows, his head should reach all the way to the ground. One may not bow directly on a stone floor, but rather, should prepare mats or any other covering upon which to bow. Some do not bow directly on any surface without a covering.
The Chazzan needs to keep his feet together during the Amidah. He should therefore be helped up after bowing.
Kohanim wash their hands up to the wrist before Birchat Kohanim.
One stands for those recitations of V’hakohanim that require bowing.
Some have a break following Musaf, for those who do, the break should be of at least 45 minutes (if possible).
