The first step is to load the video or find the video on YouTube, Vimeo, or any video hosting platform.
Once you find the campaign of your choice and select it, go to the Design and Writing Assets section > scroll down to Tokens > Web and Publishing. here you will see the different sections that will appear on the landing page including bodies and headlines.
You will want to scroll down to the landing page body copy. From here click the source button on the top left-hand side and paste your image into the copy either at the top or the bottom then click source again.
Once this is finished, hit save and publish on the bottom of the screen.
*PLEASE NOTE* you will not be able to view your landing page until your campaign is Published and no longer in Draft mode.