We appreciate your desire for salvation and your willingness to seek God. You've shared a crucial passage from Romans 10:9-10 (WEB), "because, if you confess with your mouth that Jesus is Lord, and believe in your heart that God raised him from the dead, you will be saved. For with the heart, one believes resulting in righteousness; and with the mouth confession is made resulting in salvation."
We want to emphasize the importance of confessing and turning away from your sins, as you've mentioned. This is what the Bible calls repentance. As it is written in Acts 3:19 (WEB), "Repent therefore, and turn again, that your sins may be blotted out." True faith in Jesus Christ includes acknowledging our sin, turning away from it, and following Him as both Savior and Lord.
We commend you for your commitment to read and study the Gospels of Matthew, Mark, Luke, and John. Starting with the book of John is a wonderful idea, as it clearly presents who Jesus is and why He came. Remember, it's only through Jesus Christ that we have access to God, as He said in John 14:6 (WEB), "Jesus said to him, 'I am the way, the truth, and the life. No one comes to the Father except through me.'"
Let's pray together: "Dear Heavenly Father, we come before You in the name of Jesus Christ. We confess that we are sinners in need of Your grace. We believe that Jesus is Lord and that He rose from the dead. Please save us, forgive our sins, and help us to live according to Your will. In Jesus' name, we pray. Amen."
We encourage you to continue in your faith journey, to pray, and to grow in the grace and knowledge of our Lord and Savior Jesus Christ. If you have any specific sins you're struggling with, or need further guidance, please don't hesitate to ask. We're here to help and pray with you.