What country are you currently in right now? There may be a few easier exchanges to use if your country has one. Though Binance could be said to be the best, as said by the other comments. There's also Bittrex and KuCoin to choose from. Its a matter of preference, just look them up.

As for the best coin, well, not gonna say anything but you should do your own research first. Majority here would answer BTC since it is the first plus it is the current one with the highest ROI possible compared to other coins IF the market goes your way.