Feast of Trumpets (Rosh Hashanah)- for the anointing and crowning of the Lord Jesus Christ as King by the Sanhedrin. This is the first fall feast to be fulfilled of the three in total. The Second Coming is not yet fully complete until all three fall feasts have been fulfilled in their order and seasons as God gave them in scripture, exactly as the four spring feasts were fulfilled.
Feast of Atonement (Yom Kippur)- for the judgment of the nations as portrayed in Matthew 25. Not for the rapture. Not for the crowning of Messiah. For judgment.
Feast of Tabernacles (Succoth, Booths)- for the fulfillment of the Marriage Supper of the Lamb. When all three fall feast have been completed, the entire Second Coming is complete and all the saints will then experience the blessing of inheriting Christ's Kingdom where He tabernacles among the saints.