Problem linking tables - key values

I am trying to set up an App similar to the Orders sample App but I’m having problems.
This is what I am trying to do.

  1. Engineer on site makes requests for items. I have a table called Requested Orders. Requested Order No is the key - generated by uniqueid(). Other fields are Qty, Product Code, Date required. I also have a field in this table called Order No.
  2. Buyer in office looks at list of requests, groups them together and places an order. So buyer would enter Order number, Supplier, ETA. I have a table called Orders with this data (key is Order No) as I only need this info entered once. If there are 50 items in order then data can’t be entered 50 times against each line item.

I’m not sure how to link these tables. Can anyone help me please?