HENRIK - How do mormons baptize,what is the simbol of water?,white dress?

JOEL - Mormons baptize by immersion the same way Jesus was baptized by John the Baptist.(Matt 3:13-17) Our children are baptized after they are at least eight years old. Older people are taught the gospel and the importance of repentence and are encouraged to repent of their sins before being baptized.
Someone holding the proper priesthood authority performs the ordinance for the one being baptized. According to our Book of Mormon scripture:

23 Verily I say unto you, that whoso repenteth of his sins through your words, and desireth to be baptized in my name, on this wise shall ye baptize them—Behold, ye shall go down and stand in the water, and in my name shall ye baptize them.
24 And now behold, these are the words which ye shall say, calling them by name, saying:
25 Having authority given me of Jesus Christ, I baptize you in the name of the Father, and of the Son, and of the Holy Ghost. Amen.
26 And then shall ye immerse them in the water, and come forth again out of the water." (3 Nephi 11:23-26)

Being placed down into the water during the baptism ordinance represents our bodies being placed down into the grave after death; and then the rising out of the water represents the resurresction, where our bodies reunite with our spirits and rise up out of the grave, the same as Christ did. It also represents the candidate's new birth to a life in Christ, being born of God, thus born again of the water and of the spirit(Romans 6:4-5)
The white clothing represents purity, for after we are baptized our sins are washed away(Acts 22:16) and we are made clean and pure.
Baptism symbolizes the covenant by which people promise to come into the fold of God, to take upon themselves the name of Christ, to stand as a witness for God, to keep his commandments, and to bear one another's burdens, manifesting a determination to serve him to the end, and to prepare to receive the spirit of Christ for the remission of sins. The Lord, as his part of the covenant, is to pour out his spirit upon them, redeem them from their sins, raise them in the first resurrection, and give them eternal life.