You press 2 to equip the wand: RMB to absorb a flowerbed-spell, LMB to fire it (with a short delay)
Press 1 to equip the spade, and RMB to edit a flowerbed, and RMB again to deselect the flowerbed
Flowerbed-spells are erased on use, so you need to plan ahead for the wave (though sometimes they aren't consumed?). I had a lot of fun trying spell combinations (some are outright counterproductive, like reflect+explode lol) but the actual gameplay is not very exciting (just wait for them to bunch up and explode them). Also why are the moles trying to eat the rabbit and not the vegetation?
Anyway it's worth putting these controls on the game page so more people can try this experiment.