Reading the Book of Revelation can be challenging — the storyline twists and turns and isn't strictly chronological. The author of the Book of Revelation, Saint John the Divine, offers a transcription of seven letters and later describes strange beasts, visions of judgments, governments, demonic battles, heaven, and a new world order — a prophetic vision for the end of the world. Even through all of this there is a clear structure; take a look at the layout of the Book of Revelation:
Prologue (Rev. 1)
Letters to the seven churches (Rev. 2–3)
The throne room and the scroll with seven seals (Rev. 4–5)
Judgments and vignettes
Seal judgments (Rev. 6)
144,000; the multitude (Rev. 7)
Trumpet judgments (Rev. 8–9)
The angel and a little scroll (Rev. 10)
Two witnesses (Rev. 11)
A pregnant woman and the dragon (Rev. 12)
Two beasts (Rev. 13)
144,000 on Mount Zion; three angels; harvest of the earth (Rev. 14)
Bowl judgments and the battle of Armageddon (Rev. 15–16)
A woman on the beast and the fall of Babylon (Rev. 17–18)
The Millennium and the Last Judgment (Rev. 19–20)
A new heaven and new earth (Rev. 21)
Epilogue (Rev. 22)