Have UNO, keypad LCD, nrf24o1+, need sketch to measure Time.

So I have 2 UNO, keypad LCD shield and nrf2401+ radios. I would like to have a sketch that would measure response time between both units. I have found many sketches that involves bits and pieces of what I need but I can't quite figure out how to combine these to make it work. I have used a reaction timer using a push button and expanded the sketch to do other things. Being a beginner knowing very very little C language. This has been very daunting. I would appreciate any help. Thanks in advance.