When the debugger is stopped at a breakpoint, you can step through it using four buttons in the toolbar:
In order, the buttons are:
- Play: run to the next breakpoint
- Step over: advance to the next line in the same function.
- Step in: advance to the next line in the function, unless on a function call, in which case enter the function being called
- Step out: run to the end of the current function
When paused, the "Toggle split console" button can be used to open and close the web console to gain more insight into errors and variables: