Assuming that you've got DHCP enabled on your network, simply connect the empeg to your router.

On the front panel of the empeg, go to the about screen. It should display the IP address.

You might have an incompatibility between the empeg and your router. Throw an old, cheap 10Mbps hub into the mix. Or use a switch that's known to work with empegs. Netgear ones usually do.

It's possible that your empeg was originally configured for static IP, and isn't appearing on the correct subnet. Set your Macbook to the same subnet and then edit the config.ini file on the empeg to set it to DHCP again.