To Be Born Again- What does this mean? What does the Bible tell us?

(John 3:3,5)
“… I say to you, unless one is BORN AGAIN, he cannot see the kingdom of God … unless one is born of water and the Spirit, he cannot enter the kingdom of God.

Jesus tells Nicodemus that in order to enter the Kingdom of God, a person must be “born again.” —John 3:2, 3.
How, though, can a person be born again? “He cannot enter into the womb of his mother a second time and be born, can he?” Nicodemus asks. —John 3:4.
No, that is not what being born again means. Jesus explains: “Unless anyone is born from water and spirit, he cannot enter into the Kingdom of God.” (John 3:5)

Luke 17:21 that the “kingdom of God is within you” Holy Spirit

(1 John 3:24) And by this we know that He (Jesus)abides in us, by the Spirit whom He has given us.”

Ephesians 2:18
For through Him we both have access by one Spirit to the Father.”

For there are three who bear witness in heaven: the Father, the Word, and the Holy Spirit; and these three are one.”
(1 John 5:7)

“He who has My commandments and keeps them, it is he who loves Me. And he who loves Me will be loved by My Father, and I will love him and manifest Myself to him … and We ( Fathers,Son HolySpirit) will come to him and make our home with him.” (John 14:21)