// 18 Mar 2018 - simple program to verify connection between Arduino
// and nRF24L01+
// This program does NOT attempt any communication with another nRF24
That is in the connection test program that checks communication between the Arduino and the radio module.
The earlier examples are for communication and include a "switch roles" example that does what the OP wants.
OP, did you try the examples with the recommended version of the RF24 library.
I wrote this Tutorial in 2016 when the current RF24 library version was 1.1.7. The Tutorial code has worked without problems until very recently when updates to the library code were made which were not backwards compatible. (To be honest until someone reported a problem with the Tutorial I was not even aware that any updates were being made to the library code - I am still using V1.1.7 for my own projects).
To access the Arduino Library Manager from the Arduino IDE go to Tools / Manage Libraries. After a short delay it wll display a list of all the possible libraries that can be installed. Scroll down to the RF24 library and you can then select the version you wish to install.
It is likely that the Tutorial will work with newer RF24 library versions than V1.1.7 but I don't know which is the first version that is not backwards compatible.