The short version to tape to the enclosure
A White's tree frog sitter needs numbers, not impressions, so the note taped to the glass should list the warm-side daytime reading, the cooler night reading, and the humidity band this frog normally lives in. Write the readings exactly as your own thermometer and hygrometer show them in their fixed positions, because moving a probe even a few inches changes the number.
Heating: what the sitter checks morning and evening
Heating for a White's tree frog is mostly about confirming the gradient still exists each morning and evening. The note should say where the heat source sits, which thermostat controls it, and what the warm basking area and the cooler retreat should each read. Tell the sitter never to add a second heat source or move the enclosure nearer a radiator or sunny window to chase a low reading, because a glass tank in direct sun can overshoot faster than a frog can move away. If it reads high, the instruction is to switch the heat source off at the thermostat, open ventilation as you describe, and contact you or the backup contact straight away.
Lighting and the timer rhythm
Lighting for a White's tree frog runs on a timer, and the sitter's job is to confirm the timer still works rather than to improvise a schedule. Leave the exact on and off times for the daylight lamp and the low-level UVB tube, note where the spare bulb lives, and say plainly that a dark enclosure at night is correct — this frog hunts and calls after lights-out, and a night lamp left on disrupts that rhythm. If a bulb fails, the instruction is to fit the named spare or leave the frog without that lamp for a short stretch and message you, never to substitute a stronger household bulb.
Humidity, misting and the water bowl
Humidity instructions for a White's tree frog need the misting frequency, the time of day you mist, and the water treatment you use for both spray and bowl. White's tree frogs drink droplets from leaves and soak in their bowl, so the note should say how full the bowl sits, how often it is emptied and refilled, and that tap water is treated exactly as you describe before it touches the enclosure. A light evening mist that beads the leaves, plus a clean bowl, matches how this species actually drinks far better than constant fog.
What a worrying change looks like for this frog
A White's tree frog that stops perching in its usual spots, sits hunched on the floor through the day, refuses food across several evenings, or shows skin that looks dull, blotchy or stuck mid-shed deserves a prompt call to you and then to the exotic vet whose number is on the note. Tell the sitter to photograph the thermometer, the hygrometer and the frog itself before calling, because those three pictures answer most of your questions from a distance.
Leaving the note so it actually gets used
The White's tree frog handover works when the one-page heat, light and humidity note lives on the enclosure, the spares are labelled, and the sitter has walked the setup once with you before you leave. That rehearsal turns a page of instructions into a routine the sitter trusts. Keeping those rehearsed heat and light instructions in KinsLe's Care Pass means your sitter opens one clear handover instead of hunting through messages while a frog waits.