One of the keys to properly interpreting Revelation is to realize it tells the same story of Christ's second coming and victory from seven different perspectives. Each perspective begins with John seeing something new and ends with Jesus victorious, often pictured as Him sitting down on the throne.
Chapter four begins the second of these seven perspectives. It's a glimpse into the throne room of God, where we see that all of reality is theocentric; that is, all that is radiates out from God.
You'll also start to notice in chapter four some of the strange descriptions that John gives to things, such as the four living creatures surrounding the throne of God:
In the center, around the throne,
were four living creatures,
and they were covered with eyes, in front and in back.
The first living creature was like a lion,
the second was like an ox,
the third had a face like a man,
the fourth was like a flying eagle.
Each of the four living creatures