Hi Hein,
If you have a specific bit of code to add then by all means ask and someone will tell you where that goes.
If you are asking generally, then the best way to identify embed points is by having a passing familiarity with the code that's being embedded. To get that I mostly use right-click / source when selecting embeds.
If you understand the Form and Browse to be "event handlers" then the "stage" makes more sense because that allows you to see all the times the procedure is called, and what event / stage it is in at that time.
But reading the generated code you can see how that stage in turn calls multiple specific routines.
cheers
Bruce