May 1829
Joseph Knight helped by bringing foolscap writing paper, and D&C 12 was directed to him.
While translating the Book of Mormon, probably in 3 Nephi 11 or 19, Joseph and Oliver learned of the Aaronic Priesthood and inquired of the Lord. John the Baptist appeared and conferred on them the Aaronic Priesthood on May 15.
JS-H 1:68-72
Joseph and Oliver reached the end of the Harmony Plates. Joseph said the Title Page is a literal translation taken from the very last leaf of the Original Book of Mormon. They sent the Title Page to the U.S. District Court for the Northern District of New York to be copyrighted.
Instead of starting over to translate the first part that had been lost, they were instructed to translate the Plates of Nephi, which they did not have. ". . . because the account which is engraven upon the plates of Nephi is more particular . . . Therefore, you shall translate the engravings which are on the plates of Nephi." (D&C 10:39-41)