When the installation is 'on' (plugged in), the water and alcohol containers will be empty within a few days. Please check regularly.
In the flask with yellow liquid you put (distilled) water. Distilled if you have, if not use tap water. In the flask with transparent liquid you put denatured alcohol in 1:4 ratio. One unit of alcohol and 4 units of water. You can find pure alcohol in a container, in the Aroma Lab next to the sink.