For safely trading it's better that you should join the top 5 exchanges so you can assure that your funds will not be frozen in case you will need it anytime.
https://coinmarketcap.com/exchanges/volume/24-hour/You can follow that link and find the best exchange that you like especially those with smooth interface that you can easily trade.
Only I can suggest to OP is that, choose only to make a try, not of trolling them all. Though they are of different exchanges but the process from deposit, trading and withdrawal will all just the same, there is only difference of the buying price and market volume.
Anyway, there is a time to explore and to find exchanges that brought us more profits and also we feel comfortable of using it.