How Do I set a Password on Powerline AV 200 - MAC User

The actual product is a Powerline AV 200 XAVN2001 but the drop down box wouldn't allow me to have it!

Hello - I'm setting up a wireless network in a room where my regular router (virgin super hub) can't reach.  My brother lent me some old products so I'm having trouble finding the answer I need,

I've connected my router to a Powerline Av500 Gigabit and then plugged in a Powerline AV 200 XAVN2001 into the 'dead' room.  I've reset the factory defaults and it's broadcasting a wifii signal called 'Netgear'.  It's working well, I'm using it to type this messgae. Hoorah!

But... I now have an open network.  How do I add a password?  I can't seem to figure out how I find the settings page.  I've downloaded the utility software BUT I'm on a MAC and it seems to be PC only.

I would have thought that it's just a URL but I can't find any reference to it.

Thank you in advance!

J.