Okay. I'll do it without the verses now, and then if you can look them up. (sorry) I'll also give you a little background on my bleifs on certain matters, because I think that will help clear things up.
Okay, so he dies. Then, like all spirits, he decends into the spirit realm, where all spirits go after they die. This is kind of a waiting period for spirits. All spirits will either go into a "paradise" or a "hell," depending on whether or not they lived a good life, and also where people who have died without the law. This will be a lot like it is now, except we won't have bodies. We will, however, have all the same thoughts, feelings, etc., which might kind of suck. For example (and I know this may not be the most "appropriate" example, but I think it is most clear one) if you have an addiction to masturbation, you will still feel the need to do that all the time, but you won't have a body to do that with. That might suck. Anyway, Jesus descended into that spirit world. He went to the spirit prison and preached the gospel to all those who had died without it, such as the jews. Then he went to the paradise part of the spirit world and set up sort of a missionary thingy, whree they would go and preach to the spirits who came later (since there would necessarily be more coming all the time). ONe of the things that Christ did when he was on earth was he set up a way for the living to baptise for the dead. See pauls letter to the Corinthians, chpt 15, v 29. He also set up ways for the living to do all the other ordinances that our church beleives in, such as marriage for time and eternity, and sealing families to each other. That way, people who happen to die without an everlasting marriage might be able to still accept that later on in life. Also, people who died without accepting christ will still have a little bit of time after death, too. So essentially christ was busy setting up in the spirit world what he was setting up on earth during his life. Was that in depth enough, or do you need more?