Generally speaking, the preferred LDS method of talking about the Temple is to say as many words as possible about it without actually saying anything about it. I suppose for lots of people, if you throw enough platitudes, bad analogies and thought-terminating cliches at them, their brain will shut off or they’ll get distracted and you can move on to a new subject and forget that you never actually said anything meaningful about the original subject.
This is extremely evident in how we talk about the Temple to those who haven’t actually been to the Temple. Oddly, we teach a Temple Preparation class that doesn’t really do much “preparation”. If you are teaching such a class and want to make it a little more interesting (and relevant to the experiences the students will soon be having), I would recommend including these Church-produced resources.
First, I would start with this quote from Brigham Young, as recently quoted in GC by President Packer:
“Let me give you a definition in brief. Your endowment is, to receive all those ordinances in the house of the Lord, which are necessary for you, after you have departed this life, to enable you to walk back to the presence of the Father, passing the angels who stand as sentinels, being enabled to give them the key words, the signs and tokens, pertaining to the holy Priesthood, and gain your eternal exaltation in spite of earth and hell.”
I would then explain to the person that when we go to the Temple, in addition to learning these key words, signs and tokens, we are making sacred covenants with God. These covenants are described by Elder Hales in this illustration from his recent book. They include obedience to the Lord, chastity, consecrating our time and resources, and others. The person could search on the Church website for lots of info on all of these.
(from this book)
In addition to the signs, key words and tokens and covenants, people are taken through the story of Adam and Eve. They can see how this works by looking at this model of the Salt Lake Temple:
The different rooms and the significance of the story of Adam and Eve as told in the Temple are recounted in this article for LDS teenagers:
When you enter the temple, you will receive instructions and learn the important events of our eternal journey. You’ll learn about the creation of this world and about our first parents being placed in the Garden of Eden. You’ll learn how Satan tempted Adam and Eve and how they were cast out of the garden and out of the presence of God into our world, with its opposition in all things. Here they learned about the joys as well as the discomforts of life.After Adam and Eve were cast out of the Garden of Eden and placed in the world where we now live, they were taught the gospel, and they entered into covenants of obedience with God, just as you will in the temple. How we keep these covenants determines the nature of the life we will enjoy after this mortal experience.
In the eternal world there are kingdoms of glory. You will inherit one of these, depending on your performance in this life. The aim of the gospel and the purpose of temple marriage are not only to keep us together, but also to make us eligible for Heavenly Father’s highest reward for us—exaltation in the celestial kingdom. This kingdom is symbolized by the celestial room.
There is also special clothing that we wear in the Temple that is part of the ceremony, and then a specific design of underwear (called “the garment”) that we wear outside of the Temple. This clothing is described in this video put out by the Church:
You can see the clothing that is worn inside the Temple at the 2:09 mark.
Any other questions?