Might a document need to be linked to more than one People record? If so, you need an additional table and more complex relationships than this.
If the table does not appear in "Show related records from", then it is not related to the table occurrence specified for the current layout.
You'll need to check two things:
1) Enter layout mode and open layout setup for this layout. Note the exact name given in "Show records from".
2) Open manage | Database | Relaitonships and find the "box" with this exact name. (People, I would assume). Then find the box for documents. If documents is not appearing in the Show Related Records From drop down, then either this "box" (called a table occurrence) has a different name or it is not linked to the occurrence (box) specified in Layout setup in the Show Records from drop down.