Rosh Hashana 4:6

There is a minimum of ten verses each of malchiyos‎, zichronos‎ and shofros. Rabbi Yochanan ben Nuri says that if one recites three verses of each, he has fulfilled his obligation. We do not recite verses about remembrance, kingship‎ or shofars that have negative implications. We start each set with verses from the Torah and we complete with verses from the Prophets. Rabbi Yosi says that if one completes with a verse from the Torah, he has fulfilled his obligation.

Rosh Hashana 4:7

Of the people who lead Rosh Hashana services, it is the second person (i.e., the one who will daven musaf) who leads the shofar-blowing. On days when Hallel is recited, the first person (i.e., the one who davened shacharis) leads the recitation of Hallel. (Hallel is not recited on Rosh Hashana.)