The three books of Enoch are not part of the Bible. They are considered to be part of the Pseudepigrapha, or false writings. The 1st book was written in the period 2nd century BC -
late 1st century AD, the 2nd Book was written in the 5th – 6th century AD, the 3rd book was written in the 7th century AD. The may contain many really good things about the way we are supposed to live, but where they contradict the Bible, we should dismiss what it says, unless it speaks against eating animals.
Enoch lived thousands of years before Jesus, and died before the Flood. See Genesis 5:18-24.
There is no information about how Enoch came to Walk with God, and since he was only one of two people in the Old Testament who walked with God, we must assume that he was a very Godly person. The other person this is said about was Noah.
We hope this helps.
In the Love of the Lord,
Frank and Mary