What do Latter-day Saints do in temples?
Read Dave’s answer
Answer 1
Thank you for the A2A. Let me keep this as simple as possible.
We make covenants with God through highly symbolic rites and ordinances and rituals that teach us about God and our relationship with God and our Savior and the strait and narrow covenant path that leads to the kingdom of God of which Jesus so often spoke.
Baptism by immersion for the remission of sins (only for the dead - baptisms for the living may be performed anywhere there is enough water)
Laying on of hands for the Gift of the Holy Ghost (only for the dead - this ordinance almost always follows soon after baptism and may be performed anywhere)
Washings and Anointings
The Endowment (a “gift” of knowledge and symbolic preparation to re-enter the presence of God, i.e. the kingdom of God)
Sealings (whereby couples are bonded in the New and Everlasting Covenant whereby they and their children are bonded to them and through them in sacred eternal relationships and lineages with one another and with God and our Savior)
Through these rites and ordinances, we are able to learn more about:
God and our Savior and their love for every single one of their children here on earth
Creation and its purpose
The fall of man, i.e. the story of Adam and Eve
God’s plan of redemption for us and how through proxy ordinances and as the hearts of the fathers [and mothers] are turned to the children and the hearts of the children are to to the fathers [and mothers], immortality and eternal life can be extended fairly through faith in Jesus Christ to every person who ever lived on earth
Love and unity and the ways we should treat one another
The ways we can recognize the difference between those teachings which are from God and true and those which are man-made and false
Highly symbolic tokens, signs, rituals, and ordinances that teach those with eyes to see the mysteries of God while giving fools grounds to mock and doubt
We serve God by serving one another, our ancestors and others who have passed before.
Answer 2
The best description I can come up with is that it is a place of peace and love unlike anywhere else on earth I’ve ever been, except perhaps in wilderness areas of untouched natural beauty. But that is more likely to be a solo spiritual experience, whereas in the temple you enjoy a shared spiritual experience.