He visited when I was coaching in Saskatchewan and had a novice women's double balancing their boat in 20 minutes in windy conditions. The end positions are targets from the start positions. Avoid getting fussy about when things happen - the less you tell them at this point the quicker they'll learn a natural rowing stroke. First, a brief chat about how the blades like to be square or feathered due to the flat surfaces of the sleeves and gates, and the rounded corners on the sleeve permitting a movement that only starts the square or feather with relaxed hands. Then, with the crew in the boat on the water and you holding a rigger to keep it from tilting too far too fast, have the crew stand up with their feet on the slides.
Modern slides require an extra pair of socks under the feet to prevent digging.
Get them to see how large they can make the waves from the side of the boat. Get them to actually try to sink the boat. If the boat breaks it wasn't strong enough. Then let them try it without you holding on. This tilts the boat.