It's a bit confusing. If I understand correctly you can only control the strip in sets of three LEDs. There are 10 sets in a 1m strip.
Each set receives 24 bits. The 1 bits are long (a little more than a microsecond) and the 0 bits are short (about half a microsecond). Looks like the off time is not significant.
Send 24 bits for as many sets as you want to control. I would expect the data to get shifted through so the first bits go to the furthest set and the last bits go to the nearest set.