These verses summarize the other things that Ammon taught. His teachings all came from the holy scriptures ( plates of brass) and the records of the Nephites. Ammon had searched the scriptures, which made him “a man of sound understanding” (Alma 17:3). It is also significant to note that Aaron had his own copy of the scriptures in another geographical area (see Alma 21:9; 22:12). They apparently reproduced the writings on the brass plates onto less durable texts.
Mormon summarized Alma’s record this way: Ammon taught and bore testimony of God, the creation, his authority, the fall of man, the holy scriptures of the prophets, the apostasy of the Nephites, and the plan of redemption, which was to come through the coming of Christ (to make his Atonement). He certainly taught the king well.