Here is a video of the overall experience :)
1. Click the 'Stack' icon in the upper right-hand corner of the page
2. On the 'Merge Duplicates' page, you'll be able to see a list of duplicate contacts
3. Choose the person you would like to see merging options for and click either the blue 'duplicates' button or the blue arrow
4. Click the bubble next to the profile you would like to make the primary contact
Note: Any details that are in a duplicate profile, and are not in the primary profile, will be added to the primary.
5. Click the 'Merge Duplicates' button to merge the duplicates