What are the signs of when the world will come to an end, when will the beast rise from the underworld? And what happens before all of this, because the book of Revelations is too hard for me to understand.
The whole message of the book of Revelation is simple. “We shall overcome.” Even in the face of persecution, God will win. That is the meaning of the book in its simplest form.
The Revelation can be a little easier to understand (though not much) when you realize that it has nothing to do with the end of the world. According to the first verse of the book, the prophecies in it were to be fulfilled about 1900 years ago. When people try to interpret the book otherwise, and apply the symbols in the book to today, they come up with all sorts of strange interpretations. In fact, they often have to change their interpretation when events don’t happen the way they think they should. However, the prophecies fit nicely with the Roman persecution of the church. For instance, when it talks about a beast with seven heads, it says the seven heads are seven hills. (Revelation 17:9) Rome has always been called the city on seven hills. With this stated, then the beast has already come up against the saints, and was defeated. The beast ceased to exist around 1500 years ago, and his power against the church was broken long before that.
Your first question was about the signs of the end of the world. There is a simple answer for that, too. I don’t know. In fact nobody knows. Jesus said, “Of that day and hour knoweth no one, not even the angels of heaven.” (Matthew 24:36) In that chapter he describes the signs of the destruction of Jerusalem and the Temple by Rome, but the end of the world will have no such signs. We are to be ready today as if it is the last day of the world. Anyone who says that they know the signs of the end of the world is saying they have been given knowledge that even Jesus and the angels were not given. Those who say they know the signs of the end of the world are setting themselves up as equal to God.