Sure hope the light is not as complicated as the manual is.
Lol. The first time I was introduced to it in person, it was so confusing. But as twistedraven mentioned, the basic operation is one quick click for max brightness. Hold button to cycle through low-medium-high and let go on the one you want. You can press and hold from whether the light is on or off, as it'll just cycle through low-medium-high. Single click to turn off.
Whatever you do, don't double click when the light is on...until you're comfortable with the basic operations listed above. But once you're comfortable, you can double click on any of the low/medium/high you're on to switch between slightly brighter vs slightly darker levels.
Whatever you do, don't double click till the cows come home...until you're ready to "program" the alternate level for each of the low/medium/high modes.
Optional nice feature is quick click 4 times from off to check battery level.
I love the Zebralight UI, but it definitely took time to fully understand it. And in some ways (to me), its not a good UI for when you're in a hurry if you like switching modes. When I'm in a hurry but don't want max level, I still activate the wrong mode from time to time..or even strobe myself...