How do I get these darn shoes on?

Cary put Ezra down on our bedroom floor for a moment with his little Robeez shoes next to him to finish getting him dressed. He left the room for a moment and wondered why Ezra got so frustrated. I could even hear him howling from downstairs. Was he just tired? Or not wanting to be put down? Cary returned to find him sitting on the floor with his knee up and his foot stomping on the little slipper, howling as he couldn't figure out how to get them on.