rosh hashana is called “yom teruah” (bamidbar 29:1), a day of sounding the shofar, and the davening is the longest of the year. between shofar, musaf with malchiyos zichronos and shofaros, and hours in shul, what actually matters most?

1. what are the main mitzvos of the day. shofar is clearly the biblical one. is there a torah mitzvah in the davening itself, or is the long tefillah rabbinic? and what about the festive meal, the simanim at the seuda, tashlich?

2. for someone who cannot hold concentration through three hours of davening: where should the focus go. which parts are halacha and which are custom? if a person can only keep kavana for a few sections, which ones count?

3. malchiyos zichronos shofaros: what are these three sections actually doing in musaf, and why do they carry the day?

4. and the mood: is rosh hashana supposed to feel like judgment day fear, like a coronation, or like something joyful? the meal is festive and the day is called a day of judgment. how do those sit together?

bottom line: what are the essential mitzvos and ideas of rosh hashana, what is halacha versus custom, and where should a person put limited focus?