Assuming you've done things in this order:
Insert the SD Card into the Device
Plug the Ethernet Cable
Connect any other device you may want to use (USB HUB, Wi-Fi Dongle, etc.)
Power the device on
Then did you see both the power LED light up, and then the second flashing activity LED?
The Rpi should be visible on your network, but only if your router is set to dish out IP addresses to computers via DHCP. You should be able to see the IP allocated to your Rpi by connecting to your router's admin pages. If RPi's address, e.g. 192.168.1.20, then just point browser for example to
http://192.168.1.20
If no go, then I'd suggest you ensure your router is set to use DHCP, turn the Rpi power off. Now it's important to reflash the SD card as it may have been corrupted after pulling the plug in the RPi without a proper shutdown. Now go through the setup again.