Day Three of using Ubuntu and yet another question.

Today I installed Wireshark. Upon starting for the first time, I am told that "No interface can be used for capturing in this system with the current configuration"

below that is "Capture Help"
followed by "HOW TO CAPTURE - A step by step guide to a successful capture set up"
Guide is as follows:

How To Set Up a Capture

Step 1: Are you allowed to do this?

Step 2: General Setup

Step 3: Capture traffic "sent to" and "sent from" your local machine

Step 4: Capture traffic destined for machines other than your own

Step 5: Capture traffic using a remote machine

Step 1, ok !
Step 2 is where i am stuck...

You will need to make sure the machine on which you're running is configured to support packet capture, e.g. you might need a capture driver installed. The way this is done differs from operating system to operating system."

Linux

On Linux, you need to have "packet socket" support enabled in your kernel; see the "Packet socket" item in the Linux "Configure.help" file. Your distribution might enable this by default in the kernel."

Could somebody please tell me how I go about having packet socket support enabled please ?

Many thanks in anticipation