Are you fully aware how risky is trading especially you don't know anything about it? Trading isn't a joke and we should be taking this seriously because as our money is involve here and at the first place we trade to earn and not to loss so better asking yourself first if you're emotionally and financially ready for this. Well that's only my friendly tip.

As for the marketplace, just trade on  major exchange sites such as binance, bittrex and kucoin.