I am new to crypto and I want to learn how to trade but I do not know where to start. Please give me some advice on what are the best exchanges where I could learn how to trade. Your advices will be highly appreciated. 
I respect with your desire to trade, if you choose the exchanger I suggest to adjust to your desires for example look more simple, if you want to find an exchanger that has a demo then I do not know, but I suggest exchange binance and bittrex because of the look that I think is simple.You are a beginner before trading you should understand the risks of trading and have people who can teach you because you need more experienced people to help you.
Yes sir. We must look at the bigger picture rather than going really fast and completely ignoring small details. The smallest details could be the reason of being a victim of scam and other unnecessary things with regards to trading.