You click the DRESS YOUR PET button on the top of the page when you go to My Room to dress your pet with any clothes. To dress your pet you don't even have to go to the button. Just simply drag the new clothes over top of the old ones. To take off clothes, you have to go to the button and drag the clothes shown back into your dock. If you can't put items in your dock, press GET ITEMS FROM STORAGE at the top of the dock.