First make sure all clothing was fully removed as only then can it be put on her
Almost all clothes can be found in the dresser to the left of the bed, one drawer can only be opened at a time, in the top one, you'll find her nightshirt, in the middle are either panties or bra and the other thing is in the top left corner of the bed
To put a piece of clothing back on her, simply click the interaction label nest to the clothing and complete the minigame