The most difficult part, I think, of the project is getting the RF24 radios to work. Many people struggle with that as a search of this site will show.
If you read and, closely, follow Robin2's simple rf24 tutorial you should be able to get them working. That tutorial sure helped me. The code in the examples has been proven to work many many times. If it does not work for you, there is likely a hardware problem.
Get the radios to work, by themselves, using the tutorial code before adding any other functions.