I've been invited to contribute some precepts of essential latter-day saint beliefs in the "Belief Modules" section.  I think the most systematic way to go about this is to give a personal insights into the 13 Articles of Faith.  These articles are not a creed, because they are not restrictive in nature, only descriptive.  They were not devised by a council as a statement of orthodoxy, but instead were just a "laundry list" of our key beliefs that were penned by our founder in reply to a journalist's inquiry.  Our theology is vast and complex, but the articles of faith do a good job of distilling them down for general use.  These contributions will not be full, theological treatises, but for building bridges of understanding and knowledge.  I'll try to keep these as brief as possible for the sake of the modules' purpose, but to provide enough personal insights to keep them from just being a list.  The first deals with our concept of Deity.

The Mormon concept of Deity is not derived from scripture alone.  In 1820, God the Father and Jesus Christ appeared to Joseph Smith, a 14-year old farm boy from the western frontier of New York.  From that first hand experience, we gain an understanding that is in harmony with scripture, but which differs from the creeds of orthodox Christianity.

Mormons believe in a Godhead that consists of three separate, distinct Personages: The Father, the Son, and the Holy Ghost.  These are three, eternal, uncreated Beings.  They are one in spirit and purpose, but they are not simply manifestations of one single Being or Essence.

The Father is a holy, exalted Man of Holiness.  He is a material being.  (There is nothing immaterial.  Even spirit is a refined form of matter.)  The Father is what humans were created to become in their eternal progression.  He is a glorified, perfected male.  He lives in an eternal family unit.  We are his spirit children.  His interest in us is familial and paternal.  He has a personal interest in each of us. He intervenes in the affairs of mankind to guide his family on a path of eternal progress and growth.

The Son is the Firstborn of the Father in the spirit.  He is the "the beginning of the creation of God" (Revelation 3:14).  He was "brought forth" by the Father before the creation of the world (Proverbs 8:22-31).  He was "in the beginning with God" and he is a God in his own right.  

Under the direction of the Father, the Son created the physical earth on which we dwell.  Since the fall of Adam, the Son has been the Intermediary between the Father and mankind. He speaks for the Father and bears the Father's authority in all things pertaining to our well-being and salvation.  He is the God worshiped by the prophets of the Old Testament.  It is he who appeared to Abraham, Moses, Isaiah, Ezekiel, and the various prophets.  It is he who gave the law upon Mt. Sinai.

The Son became flesh and was known by the name Jesus Christ.  The Father bore witness of him to John the Baptist at the moment of Jesus' baptism and to Peter, James, and John upon a high mountain.  His mortal ministry served several purposes.  He taught the gospel, established his church, empowered it with divine authority, and showed a perfect example of mercy, kindness, compassion, and goodness.  He sacrificed his perfectly-lived, sinless mortal life as a ransom for transgressors.  He was resurrected from the dead and rose to immortal glory, inheriting all that his Father hath, including a glorified, perfected body of flesh and bone.  His perfect love and sacrifice are the means of overcoming sin and death (more on this in a future module).

The Holy Ghost or Holy Spirit is the third Personage in the Godhead.  He is a Personage of spirit, unlike the Father and the Son, who have physical, tangible bodies.  The role of the Holy Ghost is to be a Revealer of truth and to bear witness of the Father and the Son.  Through him, all revelation comes.  Even though the Holy Ghost is a spirit, this does not mean that he is amorphous or omnipresent.  He has a spirit body that appears like that of the Father and the Son.  The prophet Nephi in the Book of Mormon beheld the Holy Ghost and that he was in the form like that of a man.  The Holy Ghost communicates to us through what our scriptures call the "light of Christ" which is an inanimate spiritual essence that connects and regulates all things.

It is said that Mormons worship the Father, in the name of the Son, by the power of the Holy Ghost.  Each of the three members of the Godhead are Gods with the Father in the position of pre-eminence.  Jesus Christ and the Holy Ghost are devoted to bringing the Father's mortal children into the Father's presence in eternity.