Run Radio Test from SDK 15.3 on custom board

Hello there,

I want to run Radio Test on one nR52832 based custom board.

I have flashed the example from SDK 15.3 on the custom board using PCA10040.

I have done the recommended settings of PuTTY terminal, UART and USB

Now, I don't understand  the HW connection to run the commands shown in the documentation. 

What should be the HW setup or connections to apply the commands through terminal?