I took a few minutes to figure it out as I usually do better with analog too, but then the 2 buttons make sense, and work efficiently.

Turn it on using the button on the light, and it comes on in the last mode used.

Say it was high power-low beam,
The big button turns the high power-high beam on, or off with each push.
1st click on the small function button selects low power- low beam, big button turns low power-high beam on and off.
2nd click on small button selects fade modulation, big button switches between high, and low power.
3rd click on small button selects flash mode, big button switches between high, and low power.
4th click on small button brings it back to the high power mode.

Fast click of the big button in any mode, or power level flashes the "light horn".

Slow click of the big button in any mode, or power level jumps to high power-high beam.
I takes 3 or less clicks of the small button to select any mode, and one click of big button to select high beam/power once in desired mode.

I find it quicker and more convenient than the Cygolite that one to take their hand off the bar, and 6 clicks to go from high to low.