First Break Point

To prevent the debugger from accessing the source code that is disabled in the project, Enable Just My Code option. For more information about the Enable Just My Code, please refer to this page and this page

With Edit and Continue, you can make and apply changes to your code in break mode while debugging, without having to stop and restart the debugging session. Edit and Continue for C# happens automatically when you make code changes in break mode, then continue debugging by using Continue, Step, or Set Next Statement, or evaluate a function in a debugger window. For more details please refer to this page

For the debugger to stop correctly on breakpoints, make sure that the Suppress JIT optimization on module load option is enabled. For further details please refer to this page