Understanding the Woe Trumps is important to understanding Revelation. Revelation is a word meaning to reveal or make known and revealing the Woe Trumps is our first step to understanding the things that Rev. 1:1 KJV says are coming to pass:
The Revelation of Jesus Christ, which God gave unto him, to shew unto his servants things which must shortly come to pass; and he sent and signified it by his angel unto his servant John:
John, in prison on the Isle of Patmos, suddenly finds himself in his spiritual body, finds himself in heaven on the Lord’s Day; Rev. 1:10 KJV is where we learn this:
I was in the Spirit on the Lord's day, and heard behind me a great voice, as of a trumpet,
Taking John into the future, God shares it with us. Rev. 4:1 KJV shows heaven opening to both John and us:
After this I looked, and, behold, a door was opened in heaven: and the first voice which I heard was as it were of a trumpet talking with me; which said, Come up hither, and I will shew thee things which must be hereafter.
The voice of the first of seven angels draws our attention to the seven trumps or events that lead to the coming of the Lord. Rev. 8:13 KJV singles out the last three…The Woe Trumps:
And I beheld, and heard an angel flying through the midst of heaven, saying with a loud voice, Woe, woe, woe, to the inhabiters of the earth by reason of the other voices of the trumpet of the three angels, which are yet to sound!
Entering the timeframe of the Woe Trumps covers the five month period that Satan and his fallen angels are here and concludes at the seventh or final trump when Christ returns.
It is the five months before Christ returns that Satan and his fallen angels, referenced as locust, are loosed upon us; God is taking about them in Rev. 9: 4 KJV:
 And it was commanded them that they should not hurt the grass of the earth, neither any green thing, neither any tree; but only those men which have not the seal of God in their foreheads.
Unable to hurt grass or any green thing assures that we are not talking about locusts…We are talking about men. The subject is Satan and his fallen angels! They are able to hurt anyone not sealed by God; anyone that does not share His Truth will be convinced that Satan is Christ and that he has come to rapture them away; Rev. 9:5 KJV continues:
 And to them it was given that they should not kill them, but that they should be tormented five months: and their torment was as the torment of a scorpion, when he striketh a man.