Executing ODK in commad propmpt

Hi guys, am really new to Open Data Kit so may you kindly assist me
I am trying to set up a local server ODK and I have downloaded and followed the installation process as set out by the installer. However, I am failing to execute POSTgreSQL commandline. Once I open command prompt and type in the required paths as given out in the READ ME Text, it keeps telling me its not recognised as an operable program or batch file