This option runs from the moment you create your FanPlus account until 3 days later.
1) On the home page, scroll all the way down and find the option that says "Settings".
2) Right there, look for "More".
3) One of the first options is "Enter Your Referrer".
In that step they must enter the username of another existing account, mine beingerfas or any other ARMY member.
Why am I talking about ARMY? Because when you sign up and mention who invited you, both you and your sponsor receive coins. It's a two-for-one deal.
Once you have the coins, you can buy votes and contribute a lot with that.