Stair Master in the gym

Hi ok so ive lost a great amount of weight and i def need to tone up my legs thighs butt so im wondering Do any of you use the stair master while at the gym if so how long? How many days a week? And what part of your body have you noticed results from it? Also how long should it take to atleast firm up my back thighs/butt?? Thanks and if you have pics from results of the stairmaster please show

Thanks