Becoming a Christian begins the start of a relationship with our heavenly Father and Christian walk with our Lord and Savior Jesus Christ, the Son of God. It is through our Lord and Savior Jesus Christ that we're promised eternal life.
To become a Christian, the Bible teaches that one must first complete five essential steps. Consider, for a moment, the links that make up a chain. A chain is not one link, but many links. All the links are important and no link can be left out; otherwise, the chain is of no value.
According to the scriptures, the first link in the chain of becoming a Christian is to Hear the Gospel of Christ:

Romans 10:17 17Consequently, faith comes from hearing the message, and the message is heard through the word of Christ.
Acts 8:5-6,12-13 5Philip went
down to a city in Samaria and proclaimed the Christ there. 6When the
crowds heard Philip and saw the miraculous signs he did, they all paid close
attention to what he said.
12But when
they believed Philip as he preached the good news of the kingdom of God and the
name of Jesus Christ, they were baptized, both men and women. 13Simon
himself believed and was baptized. And he followed Philip everywhere, astonished
by the great signs and miracles he saw.