Supplier and stock Ordering management

Hi Guys

I am new to filemaker and I am hoping someone out there can help me.

I work for a small printing company and I am trying to create a stock ordering system.

I have a created a database with the following tables 

Supplier, Stock, Orders ann line items.

What I am trying to achieve is to link specific stock items to the specific supplier and then to create an order for a selected supplier to order only sock that is required from the supplier.

I have attached the database I am currently working with. ( No management  username  ) 

My problem at the moment is linking the stock to the supplier.

Hope this all makes sense and that someone is able to point me in the right direction.

Thank you all in advance.

HIOrders_Alpha1.fmp12