A man named John went into the wilderness and told people to prepare to receive this great king. This John's mother was related to Jesus' mother. In verse 35, God tells Jesus' mother, Mary, that Mary will have a son. In verse 36, God tells Mary that her relative will also soon have a son. In verses 41 to 45, Mary visits her relative.
Baptism is a ceremony with water.
God will forgive you. People received John's baptism to show that they were sorry and wanted forgiveness. In Christian baptism, we are united with Christ, and therefore we know that we have forgiveness. Because we have sinned against God, therefore we need a savior who will forgive our sins. The Gospel of Mark tells us that this savior is Jesus.