You may have spotted that all your events are recorded in "1. Period" and there is no apparent way to switch to "2. Period".
You can stop looking. The period concept comes from Dartfish Note and as the EasyTag-Note interface is created from its big brother this aspect remains. However, we created EasyTag-Note to be our easiest-to-use product by stripping Note right down to its essentials and the extra buttons and options used to manage multiple periods were hidden.
In Dartfish Note, the period name can be changed (e.g. "set" for tennis, "half" for soccer). Then with with myDartfish 360 or Dartfish Software you can choose whether you want to import a single period or all of them to the corresponding video file(s).