There are other types of events available (“loop”, “for each” to loop for each objects, …). Just click on “Other…” in the event sheet when you want to add an event.
In your case, a “For each MY_OBJECT” event is the best choice.
After a long time I figure this out incase anyone need to know you must do this:
For Each Object-
Trigger Once:
Do +(Add) Variable(Counter)+1(or 0 base) to variable ObjectVar of Object
Do +(Add) to variable (Counter)