The first step would be to go to your control panel, then to People--> Dedupe and see if there are any people waiting to be merged. Once you have handled that group, the next step is to sort your nation alphabetically. (Use the rightmost drop down list to change the sort.)

Once your nation is sorted alphabetically, you can work with the duplicates in one of two different ways.

• If your nation is small enough, you can open each pair in separate browser windows and use the profile edit feature to manually merge the records. (Add the older record's NationBuilder ID to the lower right field in the Edit page for the newer record.)
• If your nation is too large to manually dedupe, add the duplicate records to a list and export the list. Open the resulting CSV file in Excel and sort it by name. Make sure all of the information for the person is on one record (including tags). If there is information on one record that isn't on the other, add it. (FYI: You aren't likely to have to move much information.) Tag the unupdated record with "Deletable". Reimport the record with overwrite non-blank fields enabled. Add the tagged records to a list. Use batch delete to delete them.

The reasons People-->Dedupe isn't picking up your similar records include

• You have people with two versions of their first name, which the deduper will not be able to match
• You have people with two versions of their address, which the deduper also will not match.