Well, I know only a little about stocks trading, as I'm interested mostly in crypto. The procedure of trading on a stock exchange and a crypto one is practically the same. The difference lies in what you trade.
On stocks, you could practice with small portions like it's usually done at crypto exchanges such as CEX (
https://cex.io/) or Bittrex.
Unlike others at least you said you don`t know much about stock trading, most of others comments are of topic. For trading with stocks you need to be a broker or to have one, you need a licence for doing that, that`s why crypto trading attracted so many people, simply you don`t need anything except internet and some money, everything else is a piece of cake, you register on any exchange platform or on several and you sell and buy as you wish and when you wish, from that will depend will you have profit or not. There are forex and similar trading platforms, I never had anything with that because I think it`s one big scam, they are yelling about profit everywhere they can, they promise big earning, but we all know that it`s not going like that. Crypto trading is free trading and anyone can practice it, you can start with 5 or 5000 dollars, for every other kind of trading you will need a bunch of money just for start, here you can build your own way.