The seven seals represent the future history of the world until the coming of Christ, future, that is, from John's point of view. Much of it is now past or present to us. They represent things we, as christians, have to endure in this present church age.
The four horsemen represent various calamaties we christians have to endure in the world from time to time - glorification of war, war itself, famine, widespread death . . .
The fifth seal represent the saints in heaven asking God how much longer before Christ comes to the earth again.
The sixth seal represents the actual coming of Christ and the end of the persecution and power of the four horsemen.
The seventh seal shows that the stage of earth is empty and all that matters is going on in heaven now, the new heaven and the new earth.
The seven trumpets follow. They show the same time frame, but from a different perspective . . . they are an overlap of the seven seals, not a subsequent set of events.