The instructions are on it but its very simple.
Liberally spray entire plant until leaves drip. Try to get undersides as well. I try to spray at an upward angle from the bottom of the plant towards the top center, so some catches bottoms and some rains down from the mist.
Just let it dry entirely while lights are out.
Be careful breathing it in. Its not really harmful, just kind of harsh because of the cinnamon extract.