To start with this was using Logic 9 and Reaktor 5. I don't know if anything has changed on the updates but I'd assume it would work the same.
Reaktor can be opened as a 5.1 or 7.1 insert plugin on a surround channel within Logic which means that you have up to 8 inputs and 8 outputs available within it to play with. You just open the plugin, create a new ensemble then create 8 in ports and 8 out ports. They now represent the 8 insert lines from Logic's channel strip. You can wire any input to any output and place any effect, panning device or whatever you want to build, in between.
A nice thing about Logic's surround tracks is that you can drag mono or stereo audio files onto them (or any audio files containing anything up to 8 channels) If its a mono file the audio will appear at the first Reaktor input. If its stereo it will appear at inputs 1 and 2... and so on.
Another nice thing is that there are inserts available on the Master surround output channel. This can be used, for example, to decode a b-format signal for an octagonal loudspeaker array.
I don't know of any websites that explain it. I just figured it out by messing around. Surround channels in Logic are quite flexible if you use Reaktor to access the i/o.