Its more complicated to write than it is to do, once you've done it a couple times. I'll take a shot at doing better than the Zebralight text...
In any mode, keep double clicking between the "higher" and the "secondary" setting. After a few double-click cycles, instead of the double click switching between two modes, the double-click will cycle through all available secondary modes. Once you're on the one you want, turn it off (single click) to set that level as your secondary mode.
A convention used elsewhere (not by Zebralight) is H1, H2a, H2b, and H2c, to represent the high mode, and the 3 available secondary modes within "high" (or "medium" or "low"). So, a sequence of double clicks will give you something like: H1, H2a, H1, H2a, H1, H2a, H1, H2a, H2b, H2c, H2a, H2b, H2c, etc. Same works for "M" and "L." Different models have different available modes, but the same programming cycles through whatever is available. Also, remember the mode memory: if you have most recently used, for example, H2b, M1, and L2a, those are the three modes that it will go back to when you turn it on (in that example, single click to go back to H2b, double click to go back to M1, and long press to go back to L2a).
Hope that helps!
In any mode, keep double clicking between the "higher" and the "secondary" setting. After a few double-click cycles, instead of the double click switching between two modes, the double-click will cycle through all available secondary modes. Once you're on the one you want, turn it off (single click) to set that level as your secondary mode.
A convention used elsewhere (not by Zebralight) is H1, H2a, H2b, and H2c, to represent the high mode, and the 3 available secondary modes within "high" (or "medium" or "low"). So, a sequence of double clicks will give you something like: H1, H2a, H1, H2a, H1, H2a, H1, H2a, H2b, H2c, H2a, H2b, H2c, etc. Same works for "M" and "L." Different models have different available modes, but the same programming cycles through whatever is available. Also, remember the mode memory: if you have most recently used, for example, H2b, M1, and L2a, those are the three modes that it will go back to when you turn it on (in that example, single click to go back to H2b, double click to go back to M1, and long press to go back to L2a).
Hope that helps!