Setup URL Tracking on Landing Page

BACKGROUND We are using [login to view URL] for our landing pages. Currently, we have a landing page that collects user information via a form field and then passes it to the “Thank You” page. On the “Thank You” page, the user is further incentivized to share our landing page (using a unique link) via several different social channels. WHAT WE NEED We want to know (a) exactly which user shared our landing page via their social channel and (b) how many people in that user’s social channel then followed-up and filled out the form on the landing page.