How to debug with breakpoints in VS Code?

Question

I have been stuck in this place. After reading some tutorials on the Internet, when I click on the code, there will be a red dot on the left side. However, when I click on it, there is no response. No red dot appears. What is going on? Here, please help everyone~

过去多啦不再A梦 · Answer

After adding a red breakpoint, click shift-ctrl-D to open the debugger, and then click the green triangle in the expanded panel to start the script.