hooking up a ceiling Light
Sounds like you have modern wiring so it should be pretty straightforward.  The /3 cable is delivering neutral, always-hot and switched-hot (presumably red) to the switch.  

You come off the switch with /2, white to the white in the switch box, and black to the switch terminal which now has red.  (if you want the receptacle to remain switched, you could pigtail the red, new black and the switch together.)  

Then up to your light.  You're pretty much done at that point.  

If you do not want the receptacle to be switched anymore, then pull the red wire off both ends and cap it with a yellow wire nut, add tape otherwise the wire nut will fall off.  Push it into the back of the box in case the next homeowner finds a use for it.  Then change the receptacle to a new one.  The old one had a tab broken off between hot terminals, you need that tab restored.  Or you could pigtail both hot terminals if you want to.  Whichever is easier.