Satan as witnessed in the Bible is depicted as a red beast with seven heads and ten horns, which is not an actual beast, but a figurative description of the angels who ruled over the four nations of Babylon, Persia, and Greece, as well as Rome and the ten nations that broke away from Rome. This is discussed in the links below.

http://godnara.egreef.kr/bbs/board.php?bo_table=07_01_eng&wr_id=309 

Revelation chapters 12, 13, 17, and 18 prophesy about the history of the church from Jesus to the end of time and about the reality of Satan. To understand what Satan looks like, we need to start with chapter 12.

[Revelation 12:1~5] And there appeared a great wonder in heaven; a woman clothed with the sun, and the moon under her feet, and upon her head a crown of twelve stars: And she being with child cried, travailing in birth, and pained to be delivered. And there appeared another wonder in heaven; and behold a great red dragon, having seven heads and ten horns, and seven crowns upon his heads. And his tail drew the third part of the stars of heaven, and did cast them to the earth: and the dragon stood before the woman which was ready to be delivered, for to devour her child as soon as it was born. And she brought forth a man child, who was to rule all nations with a rod of iron: and her child was caught up unto God, and to his throne.

In the passage above, the woman with the crown of twelve stars foreshadows the saints who have received the Holy Spirit. In the Bible, God's temple, church, and kingdom all refer to the saints who have received the Holy Spirit. In the same vein, Jesus likened his disciples to a pregnant woman. Jesus told his disciples that he would die, be resurrected, and appear to them, but when they didn't understand, he explained it through the parable of the pregnant woman.

[John 16 :20~22] Verily, verily, I say unto you, That ye shall weep and lament, but the world shall rejoice: and ye shall be sorrowful, but your sorrow shall be turned into joy. A woman when she is in travail hath sorrow, because her hour is come: but as soon as she is delivered of the child, she remembereth no more the anguish, for joy that a man is born into the world. And ye now therefore have sorrow: but I will see you again, and your heart shall rejoice, and your joy no man taketh from you.

So the pregnant woman is referring to the disciples, and the child she gave birth to is referring to the resurrected Jesus, who demonstrated that the Holy Spirit would come upon the saints. The child borne by the woman in Revelation 12 is not an actual child, but a representation of the resurrected Jesus. When the woman gave birth to a child, a dragon tried to kill the child, which foreshadowed Satan's crucifixion of Jesus, and the child's ascension into heaven foreshadowed Jesus' resurrection and ascension into heaven. After Jesus ascended into heaven, he cast Satan (the seven archangels and ten ministering angels and the evil angels who followed them) down to earth because their sin of trying to kill God (Jesus) was exposed.

[Revelation 12 :7~9] And there was war in heaven: Michael and his angels fought against the dragon; and the dragon fought and his angels, And prevailed not; neither was their place found any more in heaven. And the great dragon was cast out, that old serpent, called the Devil, and Satan, which deceiveth the whole world: he was cast out into the earth, and his angels were cast out with him.

Therefore, in order to know the history of the churches and the actions of Satan after he was cast out of heaven, we must look closely at the prophecies that follow.