In Nehemiah.8.10, after reading Torah on the first day of the seventh month (Rosh Hashana - Rashi ibid):
וַיָּבִיא עֶזְרָא הַכֹּהֵן אֶת־הַתּוֹרָה לִפְנֵי הַקָּהָל ... בְּיוֹם אֶחָד לַחֹדֶשׁ הַשְּׁבִיעִי׃ - On the first day of the seventh month, Ezra the priest brought the Teaching before the congregation...
רש"י: ביום אחד לחדש השביעי. הוא יום של ראש השנה:
Ezra commands the congregation to celebrate the day joyfully:
וַיֹּאמֶר לָהֶם לְכוּ אִכְלוּ מַשְׁמַנִּים וּשְׁתוּ מַמְתַקִּים וְשִׁלְחוּ מָנוֹת לְאֵין נָכוֹן לוֹ כִּי־קָדוֹשׁ הַיּוֹם לַאֲדֹנֵינוּ וְאַל־תֵּעָצֵבוּ כִּי־חֶדְוַת יְהוָה הִיא מָעֻזְּכֶם׃
He further said to them, “Go, eat choice foods and drink sweet drinks and send portions to whoever has nothing prepared, for the day is holy to our Lord. Do not be sad, for your rejoicing in the LORD is the source of your strength.”
However, I don't see the Mitzvah of Shofar mentioned anywhere on that day. Why?