The datasheet --www.adafruit.com/datasheets/WS2811.pdf
The 8 bits of Red data, 8 bits of Green data, and 8 bits of Blue data get sent in msbfirst.
There's no clock.
A "0" is sent as a pulse of 0.5usec High followed by 1.2usec Low; a "1" is sent as a pulse of 2usec High followed by 1.3usec Low.
That's in "low speed mode".
A Reset is a Low held for at least 50usec (esp. between "frames".)
The tolerance for the waveforms is +/- 0.15usec. Seems rigid.
You can't do that with digitalWrite and delayMicroseconds.
I'm guessing a little, but this probably involves dickering with one of the Timers.
So, there you have it - your work's cut out for you.