You should have a cryptocurrency wallet; normally a bitcoin wallet. You can open an account with COINS.PH, COINBASE, BLOCKCHAIN, and many more.
Create an account with Cryptocurrency Exchange (such as Poloniex, Kraken, Bitfinex).
To see all Cryptocurrency Exchanges, go to: coinmarket.com.Fund your Cryptocurrency Exchange account, normally using your bitcoin wallet.
Explore & Start Trading.
Watch video below on how to use Poloniex.
Cryptocurrency Trading is equipped with a lot of risks. I advise you to dig up more info, conduct research, and analyze more reviews.
"Risk comes from not knowing what you're doing."