First of all u have to buy bitcoin to buy other currencies. So it depends upon from which country u r as many countries do not allow bitcoin to purchase. Localbitcoin website is best and operative all over the world to but bitcoin and then u can buy other cryptocurrencies by this bitcoin on other exchanges like bittrex, poloniex, binance, cryptopia and many others
So meaning to say, Buy bitcoin > transfer to exchanges > then start trading?
And if I were to convert it back to cash, its the reverse cycle?