According to the Millenium theory, such period is followed by the end of times. My question is: Before this end, is there supposed to be Last Judgement? I have read that there only exists a time of happiness but no mention was given regarding if there would be a distinction between those “good”and “bad” humans.
Millennialism (from millennium, Latin for "a thousand years"), or chiliasm (from the Greek equivalent), is a belief advanced by some religious denominations that a Golden Age or Paradise will occur on Earth prior to the final judgment and future eternal state of the "World to Come". Premillennialism sees Christ's second advent as preceding the millennium, thereby separating the second coming from the final judgment. In this view, "Christ's reign" will be physically on the earth. Source: https://en.wikipedia.org/wiki/Millennialism
Premillennialism is the view that Christ’s second coming will occur prior to His millennial kingdom, and that the millennial kingdom is a literal 1000-year reign of Christ on earth. During this time Christ will judge the nations on earth but the last judgment will not happen till the end of the millennium. Matthew 25:31-46 describes the judgment of the nations after the tribulation period and during the millennium:
When the Son of Man comes in his glory, and all the angels with him, then he will sit on his glorious throne. Before him will be gathered all the nations, and he will separate people one from another as a shepherd separates the sheep from the goats.
The sequence of events that take place at the end of the millennium are described in Revelation20:7-15. First is the defeat of Satan:
And when the thousand years are ended, Satan will be released from his prison and will come out to deceive the nations that are at the four corners of the earth, Gog and Magog, to gather them for battle; their number is like the sand of the sea. And they marched up over the broad plain of the earth and surrounded the camp of the saints and the beloved city, but fire came down from heaven and consumed them, and the devil who had deceived them was thrown into the lake of fire and sulphur where the beast and the false prophet were, and they will be tormented day and night forever and ever.
Then comes the final judgment before the Great White Throne:
Then I saw a great white throne and him who was seated on it. From his presence earth and sky fled away, and no place was found for them. And I saw the dead, great and small, standing before the throne, and books were opened. Then another book was opened, which is the book of life. And the dead were judged by what was written in the books, according to what they had done. And the sea gave up the dead who were in it, Death and Hades gave up the dead who were in them, and they were judged, each one of them, according to what they had done. Then Death and Hades were thrown into the lake of fire. This is the second death, the lake of fire. And if anyone’s name was not found written in the book of life, he was thrown into the lake of fire.
This final judgment of unbelievers occurs at the end of the Millennium, before the creation of the new heaven and earth. At this judgment, unbelievers from all the ages are judged for their sins and consigned to the lake of fire.