3 Nephi 23:14

And now it came to pass that when Jesus had expounded all the Scriptures in one, which they had written, he commanded them that they should teach the things which he had expounded unto them.

When Jesus had explained all the Scriptures to them, he told them to teach the things he had explained to them.

After Jesus had finished explaining all the scriptures they’d written, he told them to teach the things he’d just explained.