The fine print:*  New referrals must stay the comparable amount of time as you are given.  Example, if you refer 2 new members, and receive two months free hosting, they must stay the two months to allow you to acquire the full compensation.  The way it works is like this.  When you refer a new member you are eligible for one month of free hosting.  the same month that the new referral signs up, you don't pay!.  If two members sign up, that month you don't pay, if they remain members during the second month, you don't pay.   if they for some reason cancel early then you would not be eligible that month.  same goes with the 3rd referral offer.

You must simply have them enter your username in the box provided on the sign up page