In general, when user picks a local action, after that action is complete, the user will be back on the same screen they started on (and that screen is often a regular flow action).

But when user completes the action on a regular flow action, then generally the user will be on the next assignment in the flow, looking at the next screen.

At design time, when you are editing your flow, try right clicking your assignment shape and looking at "properties" and you will see a list on which you can specify what local actions should be offered to the user during that assignment.  /Eric