Festo Solenoids should be connected to the Solenoid Breakout, as seen on page 34 of
the Component Datasheets. First, make sure you have 12V power connected to the Solenoid Breakout. Then you can use one of the 2-wire jumpers provided in the kit to connect the Festo solenoid. The pins on the Solenoid Breakout are (more or less) single direction relays. So they only turn power on or off. For consistency, you should make sure the +Out pin connects to red wires, and the GND pin connects to black wires, but this isn't mandatory.
As far as programming in labview, the solenoid functions are in the WPI Library>Actuators palette. Per usual with the WPIlib, you first "open" a solenoid reference. Then you "Set" the solenoid state in your loop code. And finally, you "Close" the reference. The "Set" function takes a simple boolean input to set the solenoid on/off, so you can wire your button output straight to it.