The thief upon the cross did not have the opportunity to go through all that. All he could say was "Jesus, Remember me when you come in your kingdom!" (Luke 2:42). That was it for him! The Lord replied "today you will be with me in paradise." Being born again is a spiritual regeneration which in time to come yields outward and inner manifestations. Amen! - You're right - there's nothing complicated about Salvation - simple child-like faith in Jesus Christ.
"Therefore if any man be in Christ, he is a new creature: old things are passed away; behold, all things are become new." (2 Corinthians 5:17). I will suggest a book entitled "Born Again"
Romans 10:8-10 KJV But what saith it? The word is nigh thee, even in thy mouth, and in thy heart: that is, the word of faith, which we preach; 9 That if thou shalt confess with thy mouth the Lord Jesus, and shalt believe in thine heart that God hath raised him from the dead, thou shalt be saved. 10 For with the heart man believeth unto righteousness; and with the mouth confession is made unto salvation.