An editorial promise about Alma's missionary work

The Book of Mosiah is complicated. Several editorial promises can be found within this book.  An editorial promise is when the author promises to give an account at a later time.  There are many examples of these throughout the Book of Mormon. Here is one:

In Mosiah 21:35, Mormon mentions that when king Limhi and his people joined the Nephites in Zarahemla, they wanted to be baptized:

35 They were desirous to be baptized as a witness and a testimony that they were willing to serve God with all their hearts; nevertheless they did prolong the time; and an account of their baptism shall be given hereafter.

 This account is found in Mosiah 25:17-18

17 And it came to pass that after Alma had taught the people many things, and had made an end of speaking to them, that king Limhi was desirous that he might be baptized; and all his people were desirous that they might be baptized also.
18 Therefore, Alma did go forth into the water and did baptize them; yea, he did baptize them after the manner he did his brethren in the waters of Mormon; yea, and as many as he did baptize did belong to the church of God; and this because of their belief on the words of Alma.