You need to open freebitco.in "Refer" section, where you will find your referral links, affiliate banners and forum signature code. Then you will need to promote your referral link - post it on social networks, forums (except bitcointalk, because here ref links is forbidden), blogs. Ask your neighbours, friends to join site via your ref link. It's not very easy to find many referrals on this site, because in bitcoin community, everyone knows about this faucet.
Thank you so much! And I received a couple of announcements that a referral shared some satoshis with me. I was baffled on how it was possible for them to know my address. And am very sorry for the late reply
It's not possible to know your address for referrals. Maybe you joined Freebitco.in under someone's referral link and that person shared his received commission with his referral. Let's say, as referral you earned 1000 satoshi for someone. And that person shared 50% of these satoshi with you and you received 500 satoshi.