TBAr, your comments helped a lot to understand the diagram. Is this diagram a standard notation?
For some reason I was seeing the oval as two circles. Probably because I only have time for my hobbies late at night.
The third pin from the left is indeed the common, which makes sense given TBAr's comments on the diagram. I have the switch working, and the 3 test LEDs I hooked up light when expected. Thanks!
I am making a bread board power supply as my first project, so next step is to add in some voltage regulators selected by the switch. I'll probably have another topic soon!
Thanks again, this has been a lot of help.