Revelations, generally

It covers a variety of things about the general state of the church, world, and heavens throughout history.

The angelic throne is what the throne of heaven looks like as can be understood by humans. Interestingly, prayers fill up in a bowl and that is how God hears them. That is one of the more interesting and applicable aspects of the whole book, in my opinion.

As for the horses, the three colored horses of plague, famine, and warfare do not represent a specific event, but a general state of the world throughout history. There will be war, famine, and disease up to the second coming of Christ. If we look at the last 2,000 years, we can probably say that each of them killed off a 1/3 of all the people who ever lived and died.

The white horse is Christ, which we get from later in Revelations. Christ is warrior-conqueror.

The multi-headed beast of the ocean is a spiritual being and not the EU, Germany, or UN. I think it is probably the Leviathan discussed in Job and Psalm 74:13-14.

As for the events surrounding the second coming of Christ, that part is very nebulous. I think it was intentionally so because God does not want us to focus on it. For after all, if Christ does not know when He is coming back, then we should not obsess about it.