The book of Revelation is divided into three sections
Write the things which you have seen, and the things which are, and the things which will take place after this. (Revelation 1:19)
The Book of Revelation is the only Book with its own divine outline, found in chapter 1 verse 19, where Jesus told John to “write the things which thou hast seen, and the things which are, and the things which shall be hereafter.”
This is the key to the entire book. It is an outline of Revelation.
The Past—The Things Thou Hast Seen... Chapter 1
The Present—The Things Which Are... Chapters 2 & 3
The Future—The Things Which Shall Be Hereafter... Chapters 4-22
If you follow this divine outline, the Book unfolds very easily

"In the midst of the seven candlesticks"—The candlesticks are the churches (vs. 20). Christ is to be at the center of the Church. Our churches, our lives, are to revolve around Him. He is found constantly in the center, in the middle position, because He is the Mediator between God and men.

Jesus Christ held seven stars in His right hand (Rev. 1:16; cp. Rev. 1:20). The seven stars symbolize the messengers, the ministers of the churches. His hand securely holds the messengers with skill and strength and comfort.

Christ was not giving John a message for himself, but for the church. He was to use what Christ was giving him for the edification of believers, to build them up in the faith. This is the great purpose for Revelation, the reason why it must be taught in the church.

1. “Things which you have seen”  Past things (Revelation 1)
John had seen a vision of the Lord Jesus Christ.

"One clothed like the son of man"- The title "Son of Man" appears eighty times in the four Gospels and the book of Acts in reference to Christ as King of the coming millennial kingdom.

"Clothed with garments down to the feet"—This was the typical clothing of the High Priests as they ministered in the holy place in the Temple. Jesus is our High Priest.

"Girded about the breast with a golden girdle"—This refers to a symbol of strength and authority in the ancient world.

"Head and hair white like wool, as white as snow"—This speaks of the ancientness and righteousness of God. Daniel called the Lord "the Ancient of Days."

"Eyes like flames of fire"
The all seeing all knowing God

"Feet like bronze"- Bronze speaks of judgment. The brazen altar of the tabernacle is where sin was judged. The Lord is not only the Judge of the Church, He is the Judge of the entire world. Those who mock Him will be judged by Him one day.

2. “Things which are” (Revelation 2-3)
Present  things, The church age, This includes the messages to the seven churches (Revelation 2, 3)
Jesus gives seven messages to seven churches, wherein lies the chronological flow of church history from the beginning of the early church to the present. The problems that took place in these seven churches are the same problems that the Church faces today. In addressing the seven churches, Jesus Christ was addressing all the churches of the earth.

3. “Things which will take place after this”. (Revelation 4-22)
Future.
The things that takes place on the earth after the church leaves.
The church is raptured and taken to heaven for a seven-year period (Revelation 4:1)
1 Thessalonians 4:16-18

Chapters 6–19
The rise of the Antichrist and the deceptions of the devil
The Seven year Tribulation occurs on earth as God pours out His wrath on a Christ-rejecting, sinful world.

Chapter 19
Armageddon and the defeat of the beast and his armies (Revelation 16:13-16)Revelation 19:11-16
At the end of chapter 19, the Lord comes back to Jerusalem with His church to establish His kingdom.

Chapter 20
The millennial reign of peace and the dominion of Jesus Christ.
A thousand-year period of peace and prosperity,  follows as the Lord rules and reigns from Jerusalem. At the end of the Millennium, Satan is loosed. A final rebellion ensues before Satan is put away permanently.

Chapters 21–22
Entrance into Eternity. A new Heaven and a new Earth.
The final state and the destiny of mankind (Revelation 21:6-8)

Bible is an account of three trees

The Tree of Life
The Tree of Life was seen at the beginning of human history
Man chose not to eat of the Tree of Life in the Garden of Eden.
Man will eat freely of the Tree of Life in the New Jerusalem.

The Tree of the Knowledge of Good and Evil
The Tree of the Knowledge of Good and Evil was the one tree of which Adam and Eve were not to partake. When they disobeyed and ate of the forbidden tree, death and damnation were the result.

The Tree of Calvary
The Tree of Calvary covers our mistakes, washes away and cleanses our sins.