I've just received three small Red Cascade plants (Euonymus euorpaeus Red Cascade). The details say they grow to about 9 feet high, but I need to keep them about 3 feet maximum as they will be in pots under a window.

At the moment the plants are just stems, about 12-20 inches long and about 1/4" in diameter, without any flowers or leaves.

I don't know much about gardening or how to prune things. Can anyone give me advice on how to prune them to make them bonsai and keep the height down, while still encouraging foliage and berries?