There are many exchanges that allow you to trade with a demo account and familiarize yourself with their platform, just be careful a demo account is a good way to see if your strategy is any good but it will never replace actual trading experience, when you are trading as a practice you will never get worried about the losses you are incurring because you know that money is not real.

But once you begin to trade for real making a trade will be many times harder especially if you have been losing money for some time as you will begin to doubt yourself and the methodology you have chosen to trade the markets.