AdRoll's guide to editing campaigns, including updating the landing page parameters, can be found here.

Append the click-through URL parameters to your landing page URLs. These parameter values use macros and do not need to be manually replaced--their values will be dynamically filled by the platform when the ad is served.

Your URLs should follow the structure guidelines available here.

AdRoll HTML5 URL Parameters

AdRoll HTML5 Impression Tracking Pixel

AdRoll Native URL Parameters

AdRoll Native Impression Tracking Pixel