John began the revelation experience physically and bodily on the island of Patmos.
Revelation 1:9
I, John, your brother and companion in the suffering and kingdom and patient endurance that are ours in Jesus, was on the island of Patmos because of the word of God and the testimony of Jesus.
Soon after, he was in the Spirit in heaven.
Revelation 4:2 NIV
At once I was in the Spirit, and there before me was a throne in heaven with someone sitting on it.
After a long series of visions came a change of setting in
Revelation 17:
1 Then one of the seven angels with the seven bowls came and said to me, “Come, I will show you the punishment of the great prostitute, who sits on many waters. 2The kings of the earth were immoral with her, and those who dwell on the earth were intoxicated with the wine of her immorality.” 3 Then the angel carried me away in the Spirit into a wilderness. There I saw a woman sitting on a scarlet beast that was covered with blasphemous names and had seven heads and ten horns.
John was still in the Spirit as before but now the setting had changed to the wilderness.
He was still in a vision of seeing things with his spiritual eyes.
After another series of visions came another change of setting in
Revelation 21:
9 One of the seven angels who had the seven bowls full of the seven last plagues came and said to me, “Come, I will show you the bride, the wife of the Lamb.” 10 And he carried me away in the Spirit to a mountain great and high, and showed me the Holy City, Jerusalem, coming down out of heaven from God.
What does it mean to be "carried away in the Spirit"?
In these verses, they mean a change of spiritual setting. John's physical body remained on Patmos all these times. I see John in a trance with his eyes closed. His body was not doing much. His spirit, however, was extremely active in the connection with the Holy Spirit. He saw visions with his spiritual eyes in the spiritual realm. To show that his spirit was not disconnected from his body, when there was a change of spiritual setting, he would involuntarily move his eyeballs under the eyelids.
This is how I imagine the scenes.