Iam a begginer working in crystal reports , Got stuck in one problem and need help

Iam using database  Dynamics and created a  oledb sqlserver connection .

I have selected 4 tables from this database and trying to make invoice for a company

It contains field from different tables .

Voucher #           Doc #     Date      PO #      Reference           Movements        Running balance

                                                                                                                Credit   Debit                      balance

Here PO# is only from a different table and is not displaying in reports  I have linked this tables using a common field in these tables i.e Vendor id.  The data from PO # Field is missing or not displaying. What additional changes has to done to overcome this . Please help me . waiting for your reply.

With regards

MD Aneesuddin Arif