I have a few of those -- hold the outer ring of the asa dial with two fingers, then with your other hand, push against that little button on the bottom of the dial with a fingernail to turn the inner scale so the arrow matches the asa/iso speed you want to use.
They don't use a battery, and the cells on mine all work -- interesting match needle system. They made agold-colored deluxe model that has a color temperature measuring deal on it as well.
If the needle is not reacting, make sure the meter is fully open -- that silver metal cover at the top of the needle scale is flexible, like the roller cover on a roll top desk. Slide it all the way up and over to open the meter window to the light.
to use the meter, point it at something after opening that roller blind, then turn the knob on the side until either a black or red patch matches the needle. If it's read, use the red readings, if it's black, use the black readings.
simple.