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.
John sees a door opened in Heaven, and a voice advises him to come up to Heaven to see what is going to happen at the end of time.
 And immediately I was in the spirit: and, behold, a throne was set in heaven, and one sat on the throne.
He is transported to heaven in the spirit, and sees God sitting on the throne of Heaven.
 And he that sat was to look upon like a jasper and a sardine stone: and there was a rainbow round about the throne, in sight like unto an emerald.
When he turns to look at God, the only way he can describe the one who is on the throne of Heaven is to compare Him to precious stones and to the colors of the rainbow. This is because God is so amazing, it is hard to put a description of Him into words we can understand.
 And round about the throne were four and twenty seats: and upon the seats I saw four and twenty elders sitting, clothed in white raiment; and they had on their heads crowns of gold.
Twenty-four chairs surround the throne. Those who sit on these chairs are elders, and they are wearing golden crowns, which indicates royalty and leadership.
 And out of the throne proceeded lightnings and thunderings and voices: and there were seven lamps of fire burning before the throne, which are the seven Spirits of God.
Thunder, lightning, and voices originate from the throne of God. The seven Spirits of God are represented by lamps.
 And before the throne there was a sea of glass like unto crystal: and in the midst of the throne, and round about the throne, were four beasts full of eyes before and behind.
This scripture describes the crystal sea that is in front of the throne of God in Heaven. Four beasts full of eyes surround the throne.
 And the first beast was like a lion, and the second beast like a calf, and the third beast had a face as a man, and the fourth beast was like a flying eagle.
One beast looks like a lion, one looks like a calf, one looks like a flying eagle, and one has a face like a man’s face.
 And the four be asts had each of them six wings about him; and they were full of eyes within: and they rest not day and night, saying, Holy, holy, holy, Lord God Almighty, which was, and is, and is to come.
Each of the beasts have six wings. Once again the text mentions that they are full of eyes. (Anything mentioned more than once is even more important as it is emphasized.) The beasts do not rest at all, for they are forever worshiping the …”Holy Lord God Almighty.” This is the Lord which always has been, exists now, and forever will exist.
 And when those beasts give glory and honour and thanks to him that sat on the throne, who liveth for ever and ever,  The four and twenty elders fall down before him that sat on the throne, and worship him that liveth for ever and ever, and cast their crowns before the throne, saying,  Thou art worthy, O Lord, to receive glory and honour and power: for thou hast created all things, and for thy pleasure they are and were created.
When the beasts worshiped God, the elders joined in, throwing their crowns at His feet, and worshiping Him, as well.