Navigate to the Instagram Stories tab within the analytics view
To Add a Single Story
Select the story you wish to add
From the drop down, select a campaign you wish to add the post to.
Posts will show a green check when they are added to a campaign.
To Add Multiple Stories
Select the Blue Tool Box Icon
Select the Stories you wish to add to a campaign
Selected stories will show in green with "Assign"
Pick a campaign from the drop down to add stories