Accessing data in a dataset from a second form using C#

Let me start by saying I am new to Visual Studio. I am using Visual Studio 2008 with .NET framework version 3.5. I am programming in C#. I have been programming in a language called Dexterity used by Microsoft Dynamics GP for several years. I am trying to fill data in a SQL table. I have successfully created a window, added the table adapter and bindings and binding navigator and can delete insert and update records. The issue I am having is that the table is too large to fit all of the fields in a single form. I need to be able to open a second form but still need to access the dataset from the first form. For example, I want to add the main information for a new customer (Name address etc) and then when I am ready I want to open a form that allows me to add payment terms for that customer (if they have any). The data from both forms is stored in the same table. Is there a way to pass the dataset from the first form (which contains some of the data) to a second form which will contain additional fields from the same table and then after I have closed the second form be able to save the combined data entered in both forms using the save button on the first form?

Thanks in advance!

Lonnie