It’s a piece of cake. If you have giffgaff broadband, pop over to your profile, scroll down, and share the unique referral code that you find there. They’ll need to add that code when they sign up. Then you both get a little something special after they’ve stuck around for a couple of months (technically after their third payment). £50 credit each to use towards your broadband bills.
You’ll get rewarded for every friend you bring on board, so get sharing. You can read the full terms and conditions here if you’re interested.