The nRF2401A is a very old chip, and we don't really have any official example code for it anymore.
I'd strongly recommend you to take a look at our newer chips, for example the nRF24L01+ or the nRF51822, although neither of them offer the Direct Mode similar to the nRF2401A. All our experience shows that packed based modes most often are much easier to work with for most all applications.
