In order to understand the financial markets, you need to become financially literate. The best place to start is the LIBRARY. Start by reading introductory material that isn't highly technical. There are a lot of "XYZ" For Dummies books. Build a basic foundation and then, move up the food chain.
As you increase your understanding of financial markets, look into more specific books about topics that interest you (Equities? ETFs? Closed end funds? Mutual Funds? Options? Futures? Long term Investing? Trading? ). Read everything that you can here, at Investopedia, at Seeking Alpha. Listen to Bloomberg TV/radio. IMO, avoid the talking heads at CNBC. Initially, some of it will make sense, some will not. If you find something of interest, Google it for more depth. Until you're somewhat literate, you won't have a clue what's worthwhile versus what's BS.
Most people new to investing start off learning about equity markets (stocks and ETFs) because derivatives markets (options) involve more complicated strategies. After that, the next logical step is usually credit markets (bonds) which is the other side of capital structure.
If possible, find a mentor so that you have someone to bounce your thoughts off of. This will help you to work through what you are absorbing from your reading. If available, find an investment club to attend.
Understanding financial markets is like learning a foreign language. It takes time and effort, something most people don’t want to do and as a result of failing to do so, they often lose their money. Financial markets quickly take the money of the inexperienced and uninformed. There's a lot of junk on the web. Until you learn some of the language, you're going to be cannon fodder.
Last of all, beware of investment advice from anonymous strangers on the internet, especially those directing you to web sites for fee based sign up :->)