Mosiah 28:11

therefore he took the records which were engraven upon the plates of brass, and also the plates of Nephi, and all the things which he had kept and preserved, according to the commandments of God, and after having translated and caused to be written the records which were on the plates of gold, which had been found by the people of Limhi, which was delivered to him by the hand of Limhi:

So he took the records written on the brass plates. He also took the plates of Nephi. He took all the things he had kept safe as God commanded. He translated the records that were on the gold plates. These were the plates the people of Limhi had found. Limhi had given them to him.

So he gathered all the sacred records—the brass plates, the plates of Nephi, everything he’d protected and preserved according to God’s commands. He’d also finished translating the gold plates that Limhi’s people had discovered and brought to him.