The Invite and Share tab provides you with your referral link as well as your social share buttons.
By sharing your referral code and/or social share buttons, anyone who signs up using your link will be automatically be connected to you. They will also show up in your Referrals under your Connections tab.
Your referral link should look something like this:
The first part of the URL code directs someone to your profile. The "?ref=USERNAME" part tracks the signup and credits it to your account.