How to select the proper resistor?
a half ampere from 3.2 volts - that's 6.4 Ohm resistor. 6.8 Ohm is a standard part and only about 5% too high. You dissipate 1.6 watts. Take a 2W or 4W capable model. 0.25W model smokes, 0.5W model gets brown and 1W model burns your fingers.

Maybe you should learn Ohm's law. NOTE playing with high capacity batteries is dangerous. A short circuit is very easy to generate by accident. That can at very high probability burn your home and blow out your eyes.