Keep in mind that increasing the ISO is not a silver bullet for shooting in low light.
Set the camera to Auto ISO. Then, select a maximum ISO. Keep in mind that increasing the ISO is not a silver bullet for shooting in low light. As you boost ISO, noise increases and image quality deteriorates. Also, set the camera to the lowest native ISO available. Finally, set a minimum shutter speed. I set that at 1/1000sec. You may prefer slower shutter speeds if your subject is stationary or moving at a leisurely pace.