The 'Edit Sample Mappings' page displays a list of unmapped samples, followed by another list mapping sample IDs to subject IDs. As you can see, the mapping list is empty, which means that none of the samples in this source have been mapped yet! The list of unmapped samples appears under the heading 'Unmapped Samples' and subheading 'Sample Name'. The numbers in this list represent the sample IDs of the unmapped samples. 
The 'Edit Sample Mappings' page shows a list of IDs for unmapped samples (highlighted in red).
