First, psychologically, you can withdraw as much as you want. This is your stop-loss price. Second, technically, the support level, resistance level and how many points you stop loss are all decided in advance. There are also some technical indicators, such as volatility indicators, which are also the basis for stop loss. Third, the event, if the event occurs, what action to take.

It depends on my own understanding to get a reasonable stop-loss price by comprehensively using the three. In fact, I am a stock trader.