Before you can hope to understand Revelation, there is one thing you need to understand. That detail is explained in three of the Gospels.

And as he sat upon the mount of Olives, the disciples came unto him privately, saying, Tell us, when shall these things be? and what shall be the sign of thy coming, and of the end of the world? (Mat 24:3 KJV)

And as he sat upon the mount of Olives over against the temple, Peter and James and John and Andrew asked him privately, Tell us, when shall these things be? and what shall be the sign when all these things shall be fulfilled? (Mar 13:3-4 KJV)

And they asked him, saying, Master, but when shall these things be? and what sign will there be when these things shall come to pass? (Luk 21:7 KJV)

The disciples who spent over three years with Jesus wanted to know all about the future. They wanted to focus on the end of the world. With their minds stuck on the end of the world, they missed a series of prophecies fulfilled in front of their eyes. The disciples were so focused on the end of the world, they could not see or understand prophecies Jesus fulfilled the next day.

That is one of the major problems people face today. They open the book of Revelation focused on the last days. As long as their minds are focused on the last days, they are making the same mistake the disciples made, and will certainly miss every detail that occurs between today, and the day they are focusing on.

You need to break that trend before you can understand any details in Revelation. Once you forget the end result you want to look for, timelines in Revelation are easy to understand. That is the point when you look at Revelation the way it was written and ask yourself, "why didn't I see this before?"

John wrote about all the major events we need to pay attention to and the series of events each will follow. Those series of events and their timing cannot be altered. John recorded them in the perfect order exactly how Jesus dictated them. John never added anything or left anything out. But the series of events John recorded never seemed to fit the narratives established by most theologians. They developed their own forms of interpretation with a new set of checks and balances that never added up. Which is why we see so much confusion surrounding Revelation today.

We need to take a step back and return to the old tried and true way of understanding any book. Read the book. Take it for what it is, and allow the author to make the points and explain the details.