The "Automatically executes when reached" option is to be used when you have multiple steps stringed together that have an execution type of something other than procedural. For example, if you have a Create Version step followed by a send Notification step, you might want to execute both with only one click. To do so, you have to set the "Automatically executes when reached" property to true on each and then click the Auto-Run button: [ATTACH=CONFIG]11608[/ATTACH]. The "Automatically executes when reached" property only executes that step if the Auto-Run button has been selected.
Hope that helps!