We spoke on the phone earlier today, but for anyone else reading this thread, I will briefly summarize what was discussed.
I do not know of any detailed instructions for using a NRF24L01 module with the Zumo Robot, but the Zumo Robot for Arduino allows access to many of the pins from the Arduino. The "Arduino pin assignment table" section of the user's guide has a brief description of what each pin is used for as well as optional functions that can be disabled to free up some additional I/O pins and which ones are available at the front expansion area. Similarly, the "Front expansion" section of the user's guide has information about the pins available there.
By the way, I moved this post to a slightly more appropriate section of the forum.