That is another beast, by itself, maybe we can make that our 1st. Address, because the approach, has A “Type and Shadow” view and similarities of a “Biblical Motif”. And of course the Destruction of those cities the letters was address to and sent to in Asia Minor, by Apostle John. And remember there were no such thing as a “church” building back then neither did they use the word church! Nor did Apostle John! He said “congregation”. That is a complete study by it’s self! And should be dealt with by itself. You have to deal with “Archaeology”, Bibliography, and “geography” you have look into the cities in which the letters was address too, anything after that is all “speculations”. But most of the rest of “The Revelation of Jesus Christ” is back up by the OT text. So to fully gasp The Book of Revelation you have to see it also in the Old Testament too! Then the pieces are put together by the Holy Spirit plainly. 7 churches of Asia are not in the Old Testament.