Once clicked – a new window will open.
Before working on this step first you need to create one action in Dynamic 365. Refer to my blog How to Create Action in Dynamic 365 for reference. Activate it.
Find the action name in Message and select the same – select none in primary and secondary entity – in Event Handler – select your plugin – in Event pipeline – select PostOperation option –
Then click on Register New Step.
Once you create, it will create a new step under the plugin.