Parent child database form

I'm new to the whole Visual Studio thing.  My background is from Visual Foxpro and Access.  We are going to start moving our development to Visual Basic.  I am trying to create a simple form.  On the top it lists the customer details one record at a time.  On the bottom of the form I want a grid or list box to list the contacts for that customer.  I am struggleing with getting the relationship to work. 

I created a Dataset with the two tables.  I have edited the dataset and created a relationship between the two tables.  Unfortantly when I run the form the contact records don't filter to use only the one related to the current customer.  What am I missing???   I just need help getting these core concepts so I can dive into this thing.  I have a lot of apps that are going to be using lookup tables and such and need to understand how this whole thing works.

Any and all help is appreciated.

Thanks in advance!

Ryan