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. 
Search for exchanges with highest daily trading volume, deposit money you can afford to lose and trade. If you don't want to trade with your money in some exchanges you can open demo account and trade without money. You can't earn but it is good to start with now. Use google and look where to find exchage with demo account or check exchanges forum.