Thank you for your question.
Revelation 20:2 And he laid hold on the dragon, that old serpent, which is the Devil, and Satan, and bound him a thousand years, 3 And cast him into the bottomless pit, and shut him up, and set a seal upon him, that he should deceive the nations no more, till the thousand years should be fulfilled: and after that he must be loosed a little season... 7 And when the thousand years are expired, Satan shall be loosed out of his prison,8 And shall go out to deceive the nations which are in the four quarters of the earth, Gog and Magog, to gather them together to battle: the number of whom is as the sand of the sea. 9 And they went up on the breadth of the earth, and compassed the camp of the saints about, and the beloved city: and fire came down from God out of heaven, and devoured them. 10 And the devil that deceived them was cast into the lake of fire and brimstone, where the beast and the false prophet are, and shall be tormented day and night for ever and ever.
The difficulty with understanding the confinement of Satan during the thousand year reign of Christ and his saints comes from what we consider Satan to be.
If we consider the source of all evil in this world to be an angel of God called Satan influencing men in some supernatural unseen way, then Revelation describes him being physically bound and sealed in some deep pit, subsequently released for a bout of final deception and then thrown alive into a lake of fire and brimstone to suffer torments for eternity.
If on the other hand we consider the source of all evil in this world to lie within man himself, personified and given the name Satan, then Revelation describes symbolically, the suppression of the evil regimes of men by righteous infallible government, subsequently allowed to rise again for one last conflict and then destroyed forever with the termination of mortality on the earth.
That the lake of fire and brimstone is not intended to be understood as a literal place in the universe is indicated by what is said to be thrown into it.
Revelation 20:14 And death and hell were cast into the lake of fire...
Death is not a literal entity. It surely refers to the end of dying.
Hell in scripture is the grave. It surely refers to the end of the need for graves.
Revelation 19:20 And the beast was taken, and with him the false prophet that wrought miracles before him, with which he deceived them that had received the mark of the beast, and them that worshipped his image. These both were cast alive into a lake of fire burning with brimstone.
The beast is not a literal creature. It surely refers to the removal of the kingdom of men.
The false prophet is not a literal person. It surely refers to the removal of apostate Christianity.
If we read the text carefully Revelation actually tells us what the symbol of the lake of fire represents.
Revelation 20:14 And death and hell were cast into the lake of fire. This is the second death.
The lake of fire is simply a symbolic representation of dying again, rather than the nature or form that the second death takes.
The penalty for sin is DEATH, not eternal torment.
Ezekiel 18:4 Behold, all souls are mine; as the soul of the father, so also the soul of the son is mine: the soul that sinneth, it shall die.
In death there is no conscious existence.
Ecclesiastes 9:5 For the living know that they shall die: but the dead know not any thing, neither have they any more a reward; for the memory of them is forgotten.
Those subject to the second death cease to exist.
So the symbol is used to represent the everlasting destruction of both literal and non-literal objects.
Can I suggest that you read:
If you have further queries please ask.
I hope this helps.