In December 1831 and January 1832, Joseph Smith went about preaching and received revelations calling Newel K. Whitney as the second bishop and calling several men as missionaries.
“The Joseph Smith Translation: A Primary Source for the Doctrine and Covenants,” Robert J. Matthews, Sperry Symposium Classics, Religious Studies Center
In June 1830, Joseph Smith commenced his translation of the Bible. Revelations unfolded as he continued to study and work. The Doctrine and Covenants, Pearl of Great Price, and JST are published separately but should be seen as intertwined revelations having one root.
“Historical Context and Background,” Steven C. Harper, Casey Paul Griffiths, Doctrine and Covenants Central
D&C 71 and 73: When Ezra Booth published his complaint about Joseph Smith in a newspaper, the Lord instructed Joseph Smith and Sidney Rigdon to go out preaching.
D&C 72: Section 72 is a series of three related revelations given in response to questions about the appointment of a second bishop and what the Saints needed to be doing.
D&C 74: Section 74 explains scripture, specifically 1 Corinthians 7:14, explaining how children are holy because they are sanctified through the atonement of Jesus Christ.
D&C 75: At a conference at Amherst, Ohio, a revelation (part of section 75) was given in the presence of those attending. Several elders were called on missions. Biographies of elders mentioned in section 75, presented by Susan Easton Black, are available at Book of Mormon Central.