There are loads of platforms out there for trading, all depends on which coin you're looking to trade. Best to decide which ones you're specifically interested in and then select the platform depending on availability, active pairs, fees and liquidity. Don't just look on generic review sites, go onto the individual platforms and do the research. You will probably have to set up accounts on multiple platforms, some that are good for new(er) coins seem to be Huobi, Kucoin, Cryptopia, Binance, Cobinhood and more. Good luck.