In the Book of Mormon there are examples of missionaries teaching others about Heavenly Father. One example is Ammon teaching King Lamoni in Alma 18:24–40:
34 Ammon said unto him: I am a man; and man in the beginning was created after the image of God, and I am called by his Holy Spirit to teach these things unto this people, that they may be brought to a knowledge of that which is just and true;
36 Now when Ammon had said these words, he began at the creation of the world, and also the creation of Adam, and told him all the things concerning the fall of man, and rehearsed and laid before him the records and the holy scriptures of the people, which had been spoken by the prophets, even down to the time that their father, Lehi, left Jerusalem.
37 And he also rehearsed unto them (for it was unto the king and to his servants) all the journeyings of their fathers in the wilderness, and all their sufferings with hunger and thirst, and their travail, and so forth.
38 And he also rehearsed unto them concerning the rebellions of Laman and Lemuel, and the sons of Ishmael, yea, all their rebellions did he relate unto them; and he expounded unto them all the records and scriptures from the time that Lehi left Jerusalem down to the present time.
39 But this is not all; for he expounded unto them the plan of redemption, which was prepared from the foundation of the world; and he also made known unto them concerning the coming of Christ, and all the works of the Lord did he make known unto them.
Another example is Ammon’s brother Aaron teaching Lamoni’s father in Alma 22:4–23.
In these passages the missionaries were able to adjust their teachings to the under standing of the Lamanite kings. When we teach people we need to find out what they understand about God, then teach accordingly.
Another great example is Alma contending with Korihor the Anti-Christ in Alma 30:12–15, 37–56:
41 But, behold, I have all things as a testimony that these things are true; and ye also have all things as a testimony unto you that they are true; and will ye deny them? Believest thou that these things are true?
42 Behold, I know that thou believest, but thou art possessed with a lying spirit, and ye have put off the Spirit of God that it may have no place in you; but the devil has power over you, and he doth carry you about, working devices that he may destroy the children of God.
43 And now Korihor said unto Alma: If thou wilt show me a sign, that I may be convinced that there is a God, yea, show unto me that he hath power, and then will I be convinced of the truth of thy words.
44 But Alma said unto him: Thou hast had signs enough; will ye tempt your God? Will ye say, Show unto me a sign, when ye have the testimony of all these thy brethren, and also all the holy prophets? The scriptures are laid before thee, yea, and all things denote there is a God; yea, even the earth, and all things that are upon the face of it, yea, and its motion, yea, and also all the planets which move in their regular form do witness that there is a Supreme Creator.
45 And yet do ye go about, leading away the hearts of this people, testifying unto them there is no God? And yet will ye deny against all these witnesses? And he said: Yea, I will deny, except ye shall show me a sign.
47 But behold, it is better that thy soul should be lost than that thou shouldst be the means of bringing many souls down to destruction, by thy lying and by thy flattering words; therefore if thou shalt deny again, behold God shall smite thee, that thou shalt become dumb, that thou shalt never open thy mouth any more, that thou shalt not deceive this people any more.
48 Now Korihor said unto him: I do not deny the existence of a God, but I do not believe that there is a God; and I say also, that ye do not know that there is a God; and except ye show me a sign, I will not believe.
49 Now Alma said unto him: This will I give unto thee for a sign, that thou shalt be struck dumb, according to my words; and I say, that in the name of God, ye shall be struck dumb, that ye shall no more have utterance.
51 And now when the chief judge saw this, he put forth his hand and wrote unto Korihor, saying: Art thou convinced of the power of God? In whom did ye desire that Alma should show forth his sign? Would ye that he should afflict others, to show unto thee a sign? Behold, he has showed unto you a sign; and now will ye dispute more?
52 And Korihor put forth his hand and wrote, saying: I know that I am dumb, for I cannot speak; and I know that nothing save it were the power of God could bring this upon me; yea, and I alwaysknew that there was a God.
53 But behold, the devil hath deceived me; for he appeared unto me in the form of an angel, and said unto me: Go and reclaim this people, for they have all gone astray after an unknown God. And he said unto me: There is no God; yea, and he taught me that which I should say. And I have taught his words; and I taught them because they were pleasing unto the carnal mind; and I taught them, even until I had much success, insomuch that I verily believed that they were true; and for this cause I withstood the truth, even until I have brought this great curse upon me.
Through this we see that we cannot force anyone to believe in the Gospel. There is no ‘proof” we can give them that will make them believe. Belief requires faith and find out for ourselves. The best way to teach is to be an example of how your faith blesses you in your life.