By now what's great is that you realised there are way too many trade options out there and they all have their own perks and what not but if you know exactly what you want to do and which strategies you pally you can already start to eliminate a lot from the huge list of exchange platforms available out there. What I'd advise first of all is to understand how trading works and its operations in general.

Once you get a good understanding of that, you can then move on to do experiment that on some of the most well known exchanges, sone you might have probably heard a lot about is Binance, and if that doesn't suit you needs maybe try a platform that houses a lot of other different exchanges like bestchange. I have used this platform myself when transitioning between different altcoins and I had no problems.

Just experiment at your own will but do remember it may be risky and you might lose money, especially at the beginning.