In the Bible we read of prophets who lived on Earth many years ago. We also read stories about these prophets in the Book of Mormon. Every single one of those prophets testified of Jesus Christ.
We have prophets today who teach us about Jesus Christ, too. We may learn of Jesus Christ by following the prophets who lived long ago and prophets who live on the earth today.
Elder Robert D Hales says:
From the beginning of time, prophets have known that Jesus Christ is the Son of God, of His mortal mission, and of His Atonement for all mankind. Sacred records give the prophecies of thousands of years, not only of the first coming of our Savior but also of the Second Coming–a glorious day that will most assuredly come. (Robert D. Hales, “Finding Faith in the Lord Jesus Christ,” Liahona, Nov 2004, 70–73)
I can learn about Jesus Christ by following the prophets.