"Hello World" program for nRF24L01+? Where is a simple program that demonstrates unidirectional data transmission over a pair of nRF24L01+ radios?  It should have adequate output so that a beginner can determine that the transmission is working properly.
Here are several "getting started" articles that contain simple programs.

http://tmrh20.github.io/RF24

https://groups.google.com/forum/#!topic/nrf24-arduino/VaC2U5D1o_s

http://arduino-for-beginners.blogspot.com/2013/02/setup-nordic-nrf24l01-rf-modules-to.html