Adam and Eve were created in three parts. Body (flesh), Soul (emotions, thoughts), and a Spirit (like the wind, unseen but you can feel it).When they sinned or rejected God in the Garden of Eden, their spirit died leaving them with just a body and soul.
We are all born spiritually dead because of Adams blood line being the human race.
When Jesus died on the cross, He said "it is finished or paid in full" His blood was shed to pardon us. All we have to do to receive His pardon is believe we are spiritually dead in sin and accept His gift of grace.
At that very moment we become baptised in the Spirit, spiritually born again or born from above. We are filled with the Holy Spirit that brings a new birth, comfort, guidance and understanding. We now have three parts again, body, soul and spirit.
Here is what Scripture says about this.John 3:1-2 (AMP)
1 NOW THERE was a certain man among the Pharisees named Nicodemus, a ruler (a leader, an authority) among the Jews,
2 Who came to Jesus at night and said to Him, Rabbi, we know and are certain that You have come from God [as] a Teacher; for no one can do these signs (these wonderworks, these miracles—and produce the proofs) that You do unless God is with him.
One of the Pharisees came to see Jesus privately by night, maybe so he would not be exposed to the other religious leaders. He started complementing Jesus for the miracles He was performing saying you must be from God. Jesus pulled the rug from under his feet shocking this man with the following.
John 3:3 (AMP)
3 Jesus answered him, I assure you, most solemnly I tell you, that unless a person is born again (anew, from above), he cannot ever see (know, be acquainted with, and experience) the kingdom of God.
Note that water referenced in verse 5 represents the Spirit, it is not literal. You do not have to be baptised in water to be saved or be born again. It is merely an outward testimony of your faith in Christ Jesus.
John 3:5-6 (AMP)
5 Jesus answered, I assure you, most solemnly I tell you, unless a man is born of water and [even] the Spirit, he cannot [ever] enter the kingdom of God.
6 What is born of [from] the flesh is flesh [of the physical is physical]; and what is born of the Spirit is spirit.
If you are not born again, from above, the Spirit will not be in you and you will not be able to understand the things of God nor enter into His Kingdom.
When I accepted His pardon at a very young age, for a week it felt like I was walking on air. Not everyone feels like I did, Muslims have said that when they are born of the Spirit, they note the colors of nature. The green grass and leaves and the blue sky. Some feel peace, a sense of belonging. Scripture likens the Holy Spirit like the wind. You can't see Him and but can feel Him and see His results. As you grow in the Spirit, you can even hear His gentle voice.
John 3:8 (AMP)
8 The wind blows (breathes) where it wills; and though you hear its sound, yet you neither know where it comes from nor where it is going. So it is with everyone who is born of the Spirit.