If you are in crypto trading business and you have to transfer your currency on daily basis then you should go for trusted exchange. Coinbase is the most trusted exchange in the market. It's very risky to use third parties exchanges. There are multiple things involved in using those exchanges. If you really want to use them you must investigate before keeping coin in their accounts. Most of them have less security that why they can be hacked easily by hackers. Anyhow crypto4dummies is best resource for useful crypto information and for free training i would prefer bosscrypto crypto training.