The Jerusalem Temple was not just a building. According to ancient Jewish theology, it was a model — a copy of something that existed in heaven. The earthly tabernacle Moses built in the wilderness, according to the Letter to the Hebrews, was "a copy and shadow of the heavenly sanctuary." The Temple that Solomon built was built according to plans given by divine revelation. The Temple's proportions, materials, and furnishings all corresponded to heavenly realities.
The Book of Enoch describes those heavenly realities in vivid detail. Enoch is taken through a series of heavenly houses — translated as "houses" or "palaces" or "temples" depending on the version. The outer courts are terrifying. The inner chambers are increasingly magnificent. The innermost sanctuary is the throne room of God himself, built of fire and surrounded by fire, attended by beings who themselves shine like suns.
What Enoch describes is the heavenly archetype of the Temple — the reality that the earthly building was built to represent. The walls of crystal are the walls of the Holy of Holies. The rivers of fire are the fire on the altar. The inner sanctuary, accessible only to God's closest servants, is the space behind the veil that only the High Priest could enter once a year.
This connection between Enoch's heavenly Temple and the earthly Temple in Jerusalem illuminates both. It helps explain why the Temple was designed as it was. It helps explain why the author of Hebrews insists that the real Temple is in heaven. It helps explain why Revelation describes the new creation as a temple-city.
The Book of Enoch isn't separate from the biblical tradition. It's the key to understanding it.