The first thing we see in our passage is that heaven, and indeed when God is done with it, earth, is something new. There are those who look for God to come and set up an earthly kingdom of some kind, modeled after the kingdoms of this world. Peter says in his second epistle, We look for a new heaven and a new earth, in which righteousness dwells.
The second thing we see is that the church of God, designated here as the new Jerusalem, the bride of Christ, is in heaven already, and is not going to heaven. You went to heaven, in a certain way, the day you became a Christian and thus became a member of this Bride, this Body, this holy temple. In John’s vision the church is holy and complete, already belonging to God, every stone and precious pearl in place.