It depends on what you're trying to do with the caps. It sounds like you've just been told to use them, but not why or how. Generally you want to have a capacitor (or several, probably one's fine for you) to decouple the supply pins from the chip the supply is powering (the load). This "smooths" out the voltage response of the supply. This is why some people refer to them as smoothing capacitors. You do this because the supply voltage will change based on the demand the circuit is putting on it. When your circuit tries to draw more current, the supply cannot react immediately to the extra demand so the voltage it is supplying drops. A decoupling capacitor will charge when you turn the circuit on and will discharge during these load changes to counteract the supply's drop in voltage.
If you're trying to reduce noise from the motor, then do as TokenMacGuy says.
The best thing to do is to scope the voltage between your supply pins (8 & 16) and between each supply pin and ground as you operate the circuit and see if you're getting more than a few tens of mV of ripple. If you are, place a 0.1uF cap across the offending pins as close to the pins as you can, and re-measure to confirm the reduction in noise/ripple.
If you don't have a scope and can't borrow one, just put one 0.1uF cap across the supply pins (so between pins 8 & 16), and one each between pin 8 and ground and between pin 16 and ground. Again, try to get them close to the pins on the chip. The supply header on the edge of the board might be a good place to make those connections.
Make sure that in any case you pay attention to the voltage ratings of your caps and what voltage you're placing it across.