There are three levels of Heaven, which is a dimension beyond the earthly dimension. It is not limited by space or time and God resides in the third level. However, the devil and his demons reside in the second heaven. Angels can operate in the second level to war with the devil and his demons. on the contrary, man has access to the second heaven but only those who are washed in the blood of the Lamb, Jesus. Those are the ones who have access to the third level. The throne room of God the Father is in the third heaven and this is the understanding we have from the Bible.
Man is able to access good and evil from the second level of the heavens. Therefore, many religious movements can access both good and evil from this heaven as well. However, this mixture is what causes problems. In the garden of Eden, Adam and Eve operated on earth as if they were in the third heaven. The reason is that, in the third level, there is absolute truth. There is no evil there and therefore no questions or opinions. Truth pervades all areas of life and there is love, peace, and joy. However, because of the Fall, evil invaded the earth and now we have to contend with it on earth. Most religions embrace some of the good but they have no solution for evil. Sin produces evil actions. However, Jesus came to be the solution to the sin problem.
Through Jesus, we can now be restored to the third heaven on earth. We can enter the throne room of God and commune with Him. Jesus sits at the right hand of the Father and we are seated in heavenly places in Him (see Eph 2:6). This is the Good News of the Gospel of Jesus Christ.
I recommend you read the Gospel of John where the ministry of Jesus is revealed. He came to reveal the Father and restore us who believe in Him to the Father. As a result, now we can operate from the third heaven and overcome sin and evil from our place in heaven. What a salvation, what an inheritance.