[Jaruzel]

You don't say what your current competence is, a way back when I wanted to understand how it all worked, I read this book:

https://www.amazon.co.uk/Naked-Trader-anyone-trading-shares/...

Ignoring the 'anyone can make money' byline, a lot of the book covers how it all works. Of all the trading books I've read, this was the easiest one to follow, and the only one that I actually remembered what I'd read afterwards.

As a first step into online trading, I wholly recommend it, although I wouldn't follow his tips verbatim, and your mileage may vary, also do not bet with money you can't afford to lose, etc. ( https://www.begambleaware.org/ )