128:10 A mourner in the week of shiva may not leave his home in order to go to shul for selichos, except on erev Rosh Hashana (and erev Yom Kippur – Mishnah Brurah 581:8) when many additional selichos are recited.
128:11 The shaliach tzibbur who leads the prayers on the High Holidays and the one who blows shofar on Rosh Hashana must separate themselves for three days prior from all things that might cause impurity. They should study as much as possible the meaning of all the prayers and the laws of blowing the shofar (including the deeper meanings of the prayers and the shofar’s notes, as found in the Zohar – Mishnah Brurah 581:11). Similarly, they should study works of mussar (self-improvement), which stir a person’s heart. Through this, they will develop awe of G-d and the grandeur of His glory as He arises to judge the land. If they did not find a Torah scholar to blow the shofar, they should at least make sure that the one prompting him is learned and expert in the laws of blowing shofar. That way, if a mistake is made in blowing the shofar, he will know what to do. He will also know how to check the shofar to ensure that it is kosher.