Aside from actually trying to learn and study first before going in, I always suggest that new traders should always use only a very small percentage of their total trading stack(probably 5%, depending on how much the total stack is) to start their trading. As beginners, it's highly likely for them to lose money first as they learn. They should just increase the percentage as they get confident as time goes.
I do not even advise any new trader to use a little bit of their money or a certain percentage, which most of the time, they usually do not tend to learn much that way based on practicing what they are learning. They could still blow it all away and then eventually get to add more to their position to trade. The best is just to, at least use some of the sites that offer demo trading with free money to practice, get good at your strategy, utilize it for a very long period of time and gain enough confidence before even entering the real trading world.