ScaffoldHub has already the VSCode debugging configurations settings in place, you just need to open VSCode inside the backend folder. You will know that you opened it correctly if the toolbar is pink.
Click on the Debugger tab (left).
Launch the Program.
Open the Debug Console tab (bottom).
Now that the application is running, you can place a debugger anywhere on the backend code and it will stop when it reaches the breakpoint so you can insect the application state.
Make sure your project path doesn't contain spaces. For some reason, VSCode started crashing the debug process when the project path contains spaces like /path/to/project with spaces. Instead use /path/to/projectwithoutspaces.