He learned how to suck the water into the dropper pretty quickly, and already knew how to release it. Not a lot of instruction was necessary.
The trouble came when one of the glasses spilled. Oops. Then came purposely dumping the other two all over the tray...
I was a bit frustrated with this, but bit my tongue and started again. I know he isn't being "naughty", just experimenting with his world. Toddlers don't have total impulse control. Yet again he dumped a glass on purpose. so I figured I would stop and show him how paper towels soak-up water. We put several paper towels over the wet mess, one at a time, patting the them to see the pretty water come up through.
He then enjoyed nesting the empty glasses. Though activities don't always go perfectly as planned, especially with little ones, something useful usually comes out of it!
We hung the paper towels over our shower curtain and by the end of the day we had a very colorful addition to Ty's bulletin board!