In Alma 6:4 Mormon notes: "And thus they began to establish the order of the church in the city of Zarahemla." In the previous verses, Mormon has noted two basic actions that might define what it means to "establish the order of the church": (1) In Alma 6:1 we find that "he ordained priests and elders, by laying on his hands according to the order of God, to preside and watch over the church." (2) In Alma 6:2 we find that those who repented were baptized and received into the church. (3) In Alma 6:3 we find that those of the church who did not repent were not numbered among those of the righteous.
For Mormon to specifically identify these actions might imply that these were some specific areas that had been in disorder. [Alan C. Miner, Personal Notes]
According to McConkie and Millet, the order of the Church is maintained and manifest through ordinances and ordinations. One does not capriciously lay claim to authority or priesthood office, nor can one receive the ordinances of salvation without properly complying with commandments and appropriate procedures governing their performance. [Joseph F. McConkie and Robert L. Millet, Doctrinal Commentary on the Book of Mormon, Vol. 3, p. 47]