I am trying to construct a pair of IR gloves and amd having a bear of a time.

First question... if I have the Vishay 6400 leds, and a "AAA" x 2 battery holder, what kind of resistor should I have? I got 12 ohm resistors based on one of those online calculators, but I am not too sure that is correct after having experimented with them.

I am totally ignorant when it comes to electronics stuff, so any guidance would be very much appreciated!