no power steering

so the car was sitting for a couple of months and the person i bought it from just replaced the reservoir for the power steering because it was leaking at the bottom of it. he said the system was empty of power steering so he topped it off and it was empty refilled it. now it has not lost any fluid but still do not have the assistants of the power steering.the power steering fluid is not foaming so I know it is the right liquid.