Nephi recounts that he has made two sets of plates for recordkeeping purposes, both of which were named the plates of Nephi. One set is called for convenience, (as will be noted later) the larger plates of Nephi. These contained, or were to contain, an account of the history of Nephi's people, including the reigns of kings, wars and contention, and so forth.
The other set is called for convenience, the smaller plates of Nephi. This was to give an account of the ministry. The First (and Second) books of Nephi in the current Book of Mormon are taken from this second set of plates.
Back in 1 Ne 1:17, Nephi mentioned part of the plan of his work: First, he would abridge the record of his father, then, he would make an account of his own life and ministry. at the beginning of chapter 10 he announces that he has now finished the abridgement of his father's record and proceeding with his own account, picking up with more of Lehi's prophecies.
Lehi prophesied that Jerusalem would be destroyed, and many of its inhabitants carried captive into Babylon, and that many of them would return. Then, in six hundred years, a Messiah would be born. (it's not clear whether this six hundred years was an exact or a round number).
Lehi also spoke of a prophet who was to prepare the way for the coming of the Messiah, and quotes some of the same language used by John the Baptist, ("he is mighter than I, whose shoe's latchet I am not worthy to unloose"), and said that he was to baptize in Bethabara, beyond Jordan, and hat he would baptize the Messiah. Lehi made a brief reference to the gospel that would be preached among the Jews, that the Jews would dwindle in unbelief, and that after the Messiah had been crucified and arisen from the dead, that Jesus would manifest himself by the Holy Ghost to the Gentiles.
Lehi then makes reference to a metaphor of olive culture, that the House of Israel was to be compared to an olive tree whose branches were to be broken off and scattered throughout the world. Afterwards, they would gathered again, or after the Gentiles had received the fulness of the Gospel, the scattered remnants of Israel would be gathered in, or brought to the knowledge of their Messiah, their Lord and Redeemer.
This is almost the first reference to the theme of the scattering and redemption of Israel, which occurs repeatedly throughout the Book of Mormon. Paul (Romans 11:16-25) used a similar metaphor. Later in the Book of Mormon, a far more extensive allegory is given comparing the house of Israel to an olive tree.
Nephi mentions (As he did on chapter 6) that he is not recording all his father's prophecies, but that he did record many of them in his other book.
After hearing this discourse, he wanted to see, hear, and know of all these things for himself, by the spirit of prophesy. This prompts a digression: first a declaration that the Holy Ghost is the gift of God to all who diligently seek him, in times of old, at the present, and in the future, and that the mysteries of God may be unfolded to them, and second a call to repentance and a promise of judgment on those who seek to do wickedly during their probation.