I do not have many concrete examples what the best approach is other then checking the usages, sorry
What I typically do to find the start point of any command and event, is to search for where it is instantiated.
Intellij gives you a list of were an object is instantiated by searching for usages when your cursor is on the constructor.
From there, I typically track down the usage path further on.
So from a command perspective that’s typically good enough, as those usually aren’t created at many different locations, and there is always just one command handler/usage point for a command.
For events the story is obviously different. What I have typically noticed in Axon Framework using applications, is that there are always obvious candidates for where your events are used due to the Projections you create.
The ‘unintuitive’ locations are however Event Handling Components which accumulate events from different locations/aggregates or those which serve as triggers to certain (third-party) services.
Sorry for not providing a silver bullet here. Nonetheless I hope this helps a little.