Programming for an" easy to work with" ensemble.
I would recommend that you start all Reaktor (all programming for that matter) with a basic set of sounds sounds that you know very well.
At least one of them should be a solo voice, I prefer a spoken voice.
One sound has to be a harmonic/melodic structure ( I use the first 32 seconds from Gustav Mahlers symphony 3, but a solo instrument may be better), and finally a drum loop.
I use the same sound over and over again on every new instrument, synthesizer or DSP program I start learning, one of my sounds (the voice sound) I have used for the last 10 years.

Making controllers that controls sound file/grain length.
The two videos below shows how to make a controller for grain length that goes from 0-1, where 0 is 1/1000 of the sound file length and 1 that is the full sample length.

• How to use the Grain Cloud:s Length output to set sound file length/grain length.

The next video is about:

• How to use the Grain Cloud:s Length output to scale Distance.
• Density- number of grains playing simultaneously.

Density and CPU usage. Keep an eye on the CPU meter.
You will almost certain overload your computers CPU when you work with granulation.
The video below shows what happens.

Now there is just one thing left, What to do with granulation :-)
The next page will give you an idea.