Bitfront is one cryptocurrency exchange I know that gives guidelines to beginners which makes it easy to use. Although I have never traded on this exchange but I have once explored its platform. Bitfront is a very cheap Exchange to trade with and you can also get rewarded for referring friends, it also allows the use of credit cards for the purchase of cryptocurrencies.
There are some available markets as other cryptocurrency tokens are paired with USDT, BTC and also USD. It has a good community support and a very cute interface and a good display of cryptocurrencies available for trade which is similar to many Exchanges that I have transacted on, however, it only supports seven cryptocurrencies in total which is relatively too small to me. The loading of this Exchange takes quite much of time so I didn't find it interesting and I decided not to sign up for an account but you can check it out yourselves to enable you decide whether to or not.