We do not have much Scriptural information on this topic, other than that it was celebrated and that it will be in the future, See Isaiah 66 vs. 23.
According to scripture there is a sounding of a Shofar, and a celebratory praise and worship meeting of the congregation.
In Temple times, offerings were required as described in the Book of Numbers chapter 28 vs 11-15.
According to Jewish Tradition there also appears to be a suspension of everyday occupations (see 1 Samuel 20vs 18-34 and 2 Kings 4vs 23). An example of a prohibition of trading is found in Amos 8vs 5.
Many times in the Scriptures the New Moon festivals are listed with the Sabbaths and Moadim (or Appointed Times). It is certainly a special day appointed by the Creator, a partial (but not full) Sabbath, and a reminder of the faithfulness and Divine order to which we can offer praise and thanksgiving to the Almighty Creator.
Shalom and welcome to this presentation of what is a very ancient calendar system
