The Duplicates process separates single matches from multiple matches so that you can merge duplicate records quickly.

The single matches display all of the results where the target constituent (right side) only has one matched constituent. These are separated from All Matches as they are generally easier to resolve. 

• Results are ordered by confidence score (highest first)
• Review the details of each constituent to determine whether constituents are duplicates
• For each duplicate pair, select an action or leave it as no action by default

 
The merge process is described here:

Use the merge options box to select the action you want to perform for the merge:

• No action
  Do not do anything with this pair for now.
  
• Merge Left
  Merge the right constituent into the left constituent. The left constituent is kept.
  
• Merge Right
  Merge the left constituent into the right constituent. The right constituent is kept.
  
• Not duplicates
  Mark this pair of constituents as not being duplicates. These constituents will not be matched against each other again in future duplicate checks.
  

Once you have selected your actions hit Preview and update to be taken to the preview screen. You will be shown an overview of the actions about to be taken.

Confirm the choices you have made, or Cancel to go back and make changes.

The Multiple Matches process can be found here: Duplicates - All Matches