Why do "Mormons" do family history and what is it?

Now that my children are all in school, I feel like I should be devoting my time to many worthwhile projects and especially things I have put off until a better "season" in my life. One of those is family history work.

Because Mormons believe in a life before this one and a life after, and because we believe in eternal families--families that will be together in the life after this, we do family history work. We believe that ordinances need to be done for a person to qualify for eternal life. Let's discuss eternal life versus immortality. All people will gain immortality because Jesus Christ atoned for our sins and was resurrected. We will all be resurrected. That's immortality--living forever with our body and spirit. Eternal life is life with God. In order to live with God in the same exalted state as Him, we must be obedient to his commandments and partake of the ordinances that will allow us to be with Him again. Those saving ordinances (outward sacred, formal acts performed by priesthood authority--God's authority given to man on earth--that show our inward commitment) are baptism, confirmation, ordination to the Melchizedek Priesthood (for men), the temple endowment, and the marriage sealing. When those ordinances have not been performed on earth before a person dies, those living can perform those ordinances in the temple in behalf of the deceased. Then the entire family--all posterity past, present, and future--can be eternally together or together forever with God.

Phew. That's some deep doctrine. So, Mormons want to search out our relatives and have the temple work done. We also want to learn more about our ancestors to feel connected to them.
​
That's what I should want, but mostly I feel guilt that I'm supposed to be doing family history work and I'm not. Today I went to the Family History Center in Meridian to begin. And I'm still almost as confused about what to do as I was before. Now I need to pray for the desire and direction in helping me know what to do next.