How do I change the ip address of beaglebone black via usb.

I have just got a Beaglebone black. I can see it OK using the USB but I want to use it freestanding on the network.
I can’t see the beagleboard black on my network ( so I want to change the ip address to
What is the easiest way to do this via the USB connection and windows 7 or OSX 10.9.4
That way I can have it on the network and connect to it remotely.
I used Linux a few years ago and want to use it again. I admit I am rusty now so I just need some pointers, & I don’t want to screw thing up, well not just yet.