Hello Kraken,
welcome to the community.
Fast from food for 6 hours beforehand or apply after a nights sleep. Drink 1-2 liters of water beforehand (more like 2).
An enema beforehand makes the purge come easier and will hydrate you without needing to drink so much water as I mentioned.
Smudge the area. If you wish, lowish volume music may be comforting. If you have one, keep a 5 gallon bucket for puking nearby, if you're indoors.
Keep drinking water near by.
After misting the Kambo stick use a knife to scrape the Kambo into globules of even size. Don't put so much water that it keeps dripping off the Kambo stick.
Too much excess water run-off may possibly cause some loss of potency. When you scrape with the knife it takes a minute of working it to form the globules.
Apply even burns, scraping dead skin off. apply moistened Kambo globules to the burns. lie back and let the worst pass (head pressure, possible face swelling, hot flushing sensation, etc.) Keep the globules on as long as you can to at least cause a sufficient purge. You can mist them on the skin, to get some more absorption from them.
It will cause you to feel like you hadn't drank lots of water and will cause dry mouth. Continue to drink water so the purge comes easily.
A follow up enema is beneficial to those that wish. The Kambo puts toxins into the elimination passages. And your next shit will probably be pretty foul if you wait and don't follow up with an enema. Smudge again after cleanup.
P.S. when I mention enemas I don't mean store bought mineral oil enemas, this is not healthy. I mean warm water with possible herb teas or coffee added that may assist in detoxification.
Finally I tend to hold the red bamboo for about 5 seconds on my skin.
It seems to me that a full second to a second and a half should be sufficient? Just make full contact with sufficient pressure. The skin will snub out the ember and it's heat.
In my experience as the stick burns the tip gets thinner. I use a knife to cut off the charred tip after every one or couple burns so the burn marks are of even diameter.
Best regards.