Mux Shield Newbie question...

I recently purchased an Arduino and a Mux Shield from Mayhem and I was wondering if someone with any experience with this board could point me in the right direction as to how I would go about hooking up a simple button to any of the 48 inputs. (I understand the code, but I'm really poor at electrical circuits...) I have a microswitch with two leads, which I've properly used in the Button tutorial, but the Mux Shield inputs have three pins... (Gnd, Vcc, and I/O pin(?)) I've scoured the web for a pic of how it's done, or even a generic schematic but I haven't been able to find one... Please forgive my lack of electrical circuit knowledge, I'm just getting started in this new hobby...

The analog multiplexers act just like multi-way switches. You wire the data pin just like it was a pin on the Arduino. For a switch you can just connect the switch between data and +5 and a pull-down resistor between data and ground. The input pin will be LOW when the switch is open and HIGH when the switch is closed. The +5 and Gnd connectors with each data pin are for convenience.