How do you get money in brain battle?

Could you please elaborate on the mechanisms behind earning money in a so-called "brain battle"? Are there specific tasks or challenges that participants need to complete in order to accrue financial rewards? Is there a system of rewards and punishments in place, or is it more of a competition-based earning structure? Additionally, are there any prerequisites or qualifications required to participate in such an endeavor? I'm curious about the overall dynamics and mechanics of earning money in this context.