That is THE question, isn't it?
The general rule, seems to be not putting more than 3% of account in any given trade. Even if you're very confident in it.
But in reality, people don't even set up S/L.
Navigating the trading world as a begginner can be overwelming. It's crucial to find the right strategeis and tools that suit your style. Don't be afraid of making mistakes they're part of the learning journy. Keep praticing and stay patient; growth comes with time and experience.