chezbob:
I mean anode to 5vdc and resistor, and cathode to the gnd?
Yes. They don't specify a forward voltage drop so I'm guessing roughly 1 V. That leaves 4 V across the resistor. At that voltage a 1000 Ohm (1k) resistor would pass 4 mA which is a bit low. To get the typical 20 mA you would use 1/5th the resistance or 200 Ohms. I think the closest common resistor is 220 Ohms (Red Red Brown).