Create a breakpoint in your plugin by clicking on the margin on the left of the line where you want the debugger to break. Your editor will highlight the breakpoint line, as depicted here:
In Visual Studio, click on Debug | Attach to Process from the menu.
Find the worker process (w3wp.exe) that matches your Dynamics 365 web application. If unsure, attach to all worker processes. If you cannot find the process, tick the Show processes from all users checkbox.
Run your plugin.
The debugger will then break when the execution reaches the breakpoint line.
