You don't. You follow Joseph Smith's and other Mormon leaders' idea of the same, as contained in the Mormon writings. Such things are not accepted in Christianity, so of course from a Christian perspective you would not be following God.
Let's see...
Did the fall of Adam make it so that men "might have joy" (2 Nephi 2:25), or was the fall the cause of sin and death entering into the world (Romans 5:12)? Sin and death are not joy.
Yes sin and death did enter into the world:
(Book of Mormon | Mosiah 3:11 - 12)
11 For behold, and also his blood atoneth for the sins of those who have fallen by the transgression of Adam, who have died not knowing the will of God concerning them, or who have ignorantly sinned.
12 But wo, wo unto him who knoweth that he rebelleth against God! For salvation cometh to none such except it be through repentance and faith on the Lord Jesus Christ.
However in the end we may have joy:
(New Testament | Romans 15:13)
13 Now the God of hope fill you with all
joy and peace in believing, that ye may abound in hope, through the power of the Holy Ghost.
(New Testament | 1 Peter 1:7 - 8)
7 That the trial of your faith, being much more precious than of gold that perisheth, though it be tried with fire, might be found unto praise and honour and glory at the appearing of Jesus Christ:
8 Whom having not seen, ye love; in whom, though now ye see him not, yet believing, ye rejoice with
joy unspeakable and full of glory:
(New Testament | 1 Peter 4:13)
13 But rejoice, inasmuch as ye are partakers of Christ's sufferings; that, when his glory shall be revealed, ye may be glad also with
exceeding joy.
No conflict here at all.