Answer:
Your answer can only fully be answered by a more exhaustive study on end times than what I am able to do here. A very good book I personally have is “Charting the End Times” by Tim LaHaye and Thomas Ice. This can be purchased at many places online including Amazon.com
Briefly, most of the symbols mentioned here represent the devil (the great dragon or serpent) or the kingdom he will temporarily set up here on earth before his final destruction and downfall. Seven heads and ten crowns represent kingdoms and rulers who have authority and power where the four horsemen represent calamities upon the earth as God’s judgment begins to be unleashed.
It will be much worse than any science fiction movie come to life, and it will be a terrible time for all those who must endure this. I believe Christ will return for the church (pre-trib or mid-trib theology) before the most terrible of God’s wrath is poured out, so it is important to have a personal relationship with Jesus Christ now. Of course, there will be those saved during the tribulation but it will probably cost you your life to do so then (still better than losing your eternity!)
Thanks, and again I think LaHaye’s book would be a wonderful study and it is also beautifully illustrated to help make the learning easier.
Pastor Brad