I completely understand. When you say "???" I feel like you want to know where to start, because the topic seems very complicated. And that is a completely natural feeling.
Let me give you two examples that illustrate why it is very difficult:
1. The impact of economic news
Imagine that the central bank in a country (like the U.S. Federal Reserve) decides to raise interest rates. This news could cause a significant and rapid movement in the value of that country's currency (the dollar). Why? Because investors will find that investing their money in that country has become more profitable, so they will buy dollars, which raises its value.
The problem is that this news can be announced in seconds, and you have to be ready and analyze it immediately.