Once you understand that the 6th Seal (Re 6:12-17), the 7th Trumpet (Re 11:15-19) and the 7th Vial (Re 16:16-21) are all the same event... it becomes much easier to decipher the entire series and sequencing of events.
You can think of it like this: the Seals are the broad overview of the Endtimes, from the early church years through the 2nd coming of Christ. The Trumpets are the ending chapters before the 2nd coming of Christ. The Vials are the ending pages of the Tribulation and are the wrath of God poured out up to and including Armageddon... which takes place just as Christ is ready to return.
The reason most people fail to understand Revelation is simple:
Da 12:9 And he said, Go thy way, Daniel: for the words are closed up and sealed till the time of the end.
Daniel, though having been given specific information about the "anti-Christ", did NOT know what any of it meant. And he was told that the understanding of it would be "closed up and sealed" until the end. It's now the end.
Revelation was NEVER intended to be understood by anyone within the church who would not be subjected to the events it describes. I suspect that had it been understood over the years, that would have turned many away from Christ... as they would have known the end was centuries off. Of course, they should have been ready... for their Lord comes "as a thief". We all (most of us, anyway) are gonna croak. If that ain't a thief in the night, nothing is.
Now that these events are unfolding, it can be understood... as long as you cast off all the suppositions and speculations developed over the past two thousand years... about who is who and what is what. These suppositions and speculations are, including the Four Horsemen, flat "wrong".
What I can tell you (without a 75-page disertation) is that the 6th Trumpet is in process of sounding. That means that the 6th Seal has not been opened. When that 6th Trumpet has fully sounded, it will end in a war which will kill 1/3 of mankind. This chaos will usher in the "anti-Christ", who will confirm Israel's right to the land. It will also provide for rebuilding the Temple, which will be shared with the "Gentiles" (through their use of the outter court--that's why John was told to measure the Temple but not the outter court.)
At that point, Daniel's 70th week begins, about which he was told the words were "closed up and sealed". These are the final 7 years of human government before CHrist returns and sets up His Kingdom. In the middle of these final seven years, the "anti-Christ" will stand in the Temple and declare himself... to those who know the truth. The world at large, however, will NOT know who he is. And they will believe he is God.
This is the point where Satan is thrown down to earth and he gives his power, authority and seat to the "anti-Christ", who will be supported by the false prophet in that endeavor. These two ("anti-Christ" and Flase Prophet) will be opposed by the two witnesses of God and these witnesses will prophesy for the next 3.5 years of the "TRIBULATION" (as Jesus told us it would be, in Mt 24), which is the wrath of Satan and not the Wath of GOD! The Wrath of GOD is contained in the vials, which will begin to be poured out some time before Armageddon, with the 1st Vial... with boils upon those who have received the "mark".
As I said, the 6th Seal, 7th Trumpet, and 7th vial are the exact same event... which is the second coming of Christ. The giveaway, if you will is the great hailstones... weighing a talent, each; and the great earthquake; and the sun being blackened, along with the moon being turned to blood; and the islands moved out of their places; and... etc.
The idea that Revelation is written as a sequential expose' is wrong. It is a group of events which are not entirely sequential, from chapter to chapter.
