Step 1: System Preferences
a) going to the Apple Menu (on the upper left hand corner of the screen) and selecting System Preferences; or
b) clicking on the System Preferences icon on the Dock.
Step 3: Active Network Connection
If you have successfully entered your password, the padlock icon will unlock.
NOTE : You do not have to "unlock" if you are only to view your IP address and not edit it.
Step 4: Advanced Options
Step 6: Configure IP Adress
The values for IPv4 Address, Subnet Mask and Router will be editable. Enter your desired values for the IP address and click the OK button when you are done.