2 Nephi 31:1-2 says “And now I, Nephi, make an end of my prophesying unto you, my beloved brethren. And I cannot write but a few things, which I know must surely come to pass; neither can I write but a few of the words of my brother Jacob. Wherefore, the things which I have written sufficeth me, save it be a few words which I must speak concerning the doctrine of Christ; wherefore, I shall speak unto you plainly, according to the plainness of my prophesying.” He’s saying that he’s about to die and he can only write a little more. And he chose to write of the Doctrine of Christ. Is the Doctrine of Christ really that important that he will choose that to write about over anything else? Yes. Because it shows us the way back to heaven.
But how do we get back to heaven? “… if ye shall follow the Son, with full purpose of heart, acting no hypocrisy and no deception before God, but with real intent, repenting of your sins … ye are willing to take upon you the name of Christ, by baptism … receive the Holy Ghost … He that endureth to the end, the same shall be saved … the gate by which ye should enter … ye in this strait and narrow path which leads to eternal life … I would ask if all is done? Behold, I say unto you, Nay; for ye have not come thus far save it were by the word of Christ with unshaken faith in him, relying wholly upon the merits of him who is mighty to save … press forward with a steadfastness in Christ, having a perfect brightness of hope, and a love of God and of all men … feasting upon the word of Christ, and endure to the end, behold, thus saith the Father: Ye shall have eternal life … this is the way; and there is none other way … this is the doctrine of Christ, and the only and true doctrine of the Father, and of the Son, and of the Holy Ghost.”
So, you have to
1. Follow Jesus
2. Not even think about doing something that’s not following Him
3. Repent
4. Take his name upon you (be baptized)
5. Receive the Holy Ghost
6. Endure to the end
7. Repeat steps 1, 2, 3, 6, and 7.
https://www.churchofjesuschrist.org/study/scriptures/bofm/2-ne/31?lang=eng&verse=#p