cant figure out how to get an ACK from nrf24l01

hello i have been working on these nrf24l01 transceivers for a few weeks now then to work
with small led program now I want to test distance with them .. Instead of switching pipes and all that
I have seen people using some sort of an acknowledge packet sent function of the RF24 library
and I have tryied and keep failing any tips on how to use this feature ? it is..... Auto Ack completely fixed – Just Electronics

Simple nRF24L01+ Tutorial