Jesus says that we are to first aim at, strive for, and seek His Kingdom (Luke 12:31 AMP.).
He was always telling people about the Kingdom of God. It's like a grain of mustard seed and leaven (Luke 13:18,19,21).
He said that it's here on the Earth, within us (Luke 17:21).
Romans 14:17 tells us that the Kingdom of God is Righteousness, Peace, and Joy in the Holy Ghost.
Jesus tells us how we enter into this Kingdom. We must come through the Lord Jesus Christ and be born again. There is no other way.
A person cannot be unrighteous ... an unbeliever, not yet born again ... and think that he will enter into this Kingdom. He will not inherit or have any share in the Kingdom of God until he becomes born again.
But, there is hope for this unrighteous person. We were all at this point of unrighteousness earlier in our lives. We were all unrighteous.
But ... Praise God! ... 1 Corinthians 6:11 says that now ... after we are born again ... we are washed (cleansed), sanctified (set aside by and for God and His purpose for us), and justified (forgiven and separated from sin) by the Holy Spirit. And now we are in the Kingdom of God.
You must be born again by asking Jesus to be your Savior and Lord ... just a few simple words, not a lengthy dissortation with a LOT of words, and then trust Him that it's done.
This is how you do it. Romans 10:9,10 ... Speaking the words out loud, you acknowledge and confess with your mouth that Jesus is your Savior and Lord. In your heart (your innermost being) you believe, trust in, and rely on the Truth that God raised Him from the dead, and you will be saved (born again). With your heart (your innermost being) you believe, trust in, and rely on Jesus, and you are justified ... declared righteous and acceptable to God. With your mouth, you confess... declare openly, and speak out freely your faith ... and this confirms your salvation.
Reverend Robert W. & Mary C. Butler