To either post referral or send invitation for it, you need to have an account. Its free to sign up.
After you have an account its very easy to create or send request. Follow steps below.

How to Post Referral

Click on "Post Referral" from top menu, you will see a simple form. After submission your referral will be in Pending state for review. Once approved it will be listed.

CategoryFirst is the selection of Category under which this referral falls e.g. If you want to refer the apartment you living in you can select Housing etc.
URL/TitleSecond one is title just enter the URL of the referral that you want to share.
DescriptionIn description you can describe the referral, what they offer etc.
ImageNext one is optional if there's any image you want to share you can upload that too.
TypeIn type, some businesses offer credit(Cash) on sharing referrals and some offer you points, based on it you can select "CASH" or "POINTS" in type.
Referral ValueAfter you select type you can enter the value in Cash/Points field.
End dateLast one is the end date, some times businesses offer timely based referrals which has some kind of time line, here you have option to specify that, its optional because most of times there's no end date to referrals.

How to Request for Referral

On the home page there are list of all referrals. If you find any referrals that you like, just click on the request button and it will take you to request form.

EmailJust enter the correct email where you want invitation to be sent for this particular referral.
CommentsYou can also add any comments related to that to the person who shared that request.
Once you submit the request, your request will be in "SUBMITTED" status. Now its up the person if he accepts or rejects it. You can check the status under "My Requests" in top menu. The status could be either in "REJECTED" or "COMPLETED" state, based on the person who shared that referral.