Hello @James,
You are right. Mainly I was looking at resistance calculations and I have certainly not looked at calculating for a single LED in this post. Here would be a simple schematic that you could use to calculate a resistor in a circuit.
I do have a post Choosing the correct resistor for your LED. This post will show that using the information provided in the circuit above you can use Ohm’s Law or Digi-Key’s online calculator to determine the right resistor for your simple circuit.
Thank You again for the comment!
-Robert