Like a petticoat, a chemise, and a pair of pantalets. She holds her corset in her hand.
There is also a 'pocket' on the opposite side. These were accessed though a slit in the skirt. One would keep things in their pocket, so as not to lose them or not to have to hold them all day, like a handkerchief. That is where our modern day pockets come from.
Her petticoat is of a fancy eyelet fabric. Other items are trimmed in lace and a yellow satin bow.