The New Birth is the very first act of God upon your soul in conversion. Everything else flows from it. When God the Holy Spirit regenerates you, giving you a new heart, then you will repent and believe the gospel. When you believe the gospel you are immediately justified and adopted. Paul mentions regeneration and renewing.
Regeneration is the beginning of the ongoing renewal in the life of a believer.
New life emerges from a new birth, and in that new life we are constantly being renewed. We call this the process of sanctification. The Holy Spirit dwells in you and empowers you to put off old ways and put on new obedience to God's Word. If you have truly been born again, you will become a new person and live a new life. All Christians must struggle against sin and put it to death.