Once you've added your Bank/Credit card info, you can purchase cryptocurrencies and trade them on White Shark!
Simply go to your buy page in Coinbase here.
Note: If you fund your account in bitcoin, you can only pay for things in bitcoin until you buy a different currency.
For example, If you buy 1 bitcoin you can purchase etherium with your bitcoin (ETC/BTC). But you can't buy etherium with Bitcoin Cash if you only have bitcoin. You need to buy Bitcoin Cash before you can spend Bitcoin Cash.
Set the amount you want to purchase from your account. After confirmation you can transfer to your Coinbase Pro account and start trading White Shark.