-"Repent and be baptized every one of you in the NAME
of Jesus Christ for the remission of sins, and ye shall receive the gift of the Holy Ghost"

Repentance is the act of acknowledging sins, asking for forgiveness, and turning from them. It is a state of the soul that is granted by God, and you simply cannot repent by just saying sorry and then further continuing in sin.
It is a death of the old man.

Baptism is a symbol of burial and birth(will discuss birth in the next web page):

You bury the old man, and your sins. It essentially washes you clean of all your sins, and makes you a new man. You start with a new slate and your sins are no longer on your record. This means God does not remember them anymore. It is a remission of sins.

The Gift of the Holy Ghost is the Lord's Spirit coming down from heaven and coming to live on the inside of you.

The way you will know He is living in you
is when you start to speak in an unknown language according to Acts 2:4.
The Lord's spirit will manifest inside you and give you the power over:

Flesh
Devils
And Much More