How do I access the parent class?

In this window (i only have a CharacterBlueprint right now to show you) (UE4.7):

http://puu.sh/gkVT8/a939df5aa4.png

You can see the Parent Class at the top right:

http://puu.sh/gkVTz/5806c76596.jpg

Try clicking the Name. This should open the file!