Time Line
Bible Reference

Satan & his followers thrown into the lake of fire and destroyed –

FOREVER.

(Rev 20:10 NIV)  "And the devil, who deceived them, was thrown into the lake of burning sulfur, where the beast and the false prophet had been thrown. "
(Rev 20:15 NIV)  "If anyone's name was not found written in the book of life, he was thrown into the lake of fire."
Resources.