First of what operating system are you running? windows, mac, linux?
If windows open a command prompt (start --> run --> type: cmd )
In the command prompt window type ipconfig /all
This will give output similar to this:
Ethernet adapter Local Area Connection 3:
Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : D-Link DUB-E100 USB 2.0 Fast Etherne
t Adapter
Physical Address. . . . . . . . . : 00-80-C8-38-F6-7C
Dhcp Enabled. . . . . . . . . . . : Yes
IP Address. . . . . . . . . . . . : 192.168.10.200
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 192.168.10.1
Most important is ip Adress in this case 192.168.10.200. We need an unique address for the arduino, so we add 1 to the last number: 192.168.10.201
We still need to know if this address is free so the next command we type is ping 192.168.10.201
C:\>ping 192.168.10.201
Pinging 192.168.10.201 with 32 bytes of data:
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Ping statistics for 192.168.10.201:
Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),
We get a timeout so the address is free.
Now open webserver example and search for the part shown below
// Enter a MAC address and IP address for your controller below.
// The IP address will be dependent on your local network:
byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
byte ip[] = { 192,168,1, 177 };
Change the ip adress to your newly created address.
In this example that would be:
byte ip[] = { 192,168,10, 201 };
Download the code to your arduino.
Now open your web browser and type in the following adress http://192.168.10.201 and see the magic.
Hope this helps to get started.