Demonstration DB to get familiar with the LINK / LINKED field types. The linking DB is VISITS.PDB which links to from.pdb and at.pdb. Just look at the properities of the PDBs and modify according to own needs.
For the link/linked feature to function correctly, it is crucial to correctly define the field names and field numbers. Just explore the definitions in the DBs provided as an example. VISITS.ZIP has the following files: VISITS.PDB, from.pdb, to.pdb and manual.htm. Read a brief description of the DB in the manual.htm file.