How to set up user accounts on ReadyCloud?

First, I am a COMPLETE IDIOT when it comes to computer stuff! I'm sorry if this topic is in the wrong forum, I'm just lost at this point, and frustrated beyond belief. My wife got me a ReadyNAS 426, and all I want to do is add accounts to the cloud for my family, so that my wife can have her own account on the cloud, my sons can each have their own accounts, and I can have mine. I have read everthing I could get my hands on, watched YouTube videos till I wanna puke, and still I cannot figure out how to do this. Please, can ANYONE help me with steps on how to add accounts to the ReadyCloud via my RN426 NAS? I would so appreciate it...