Plz help me understand the code behind dataBindingNavigator in c#.net2005?

hi I am learning c#.net 2005 by building a project with a ACCESS db, now in the data source explorer, i can directly pull the entire dataSet onto the win form. there will be a bindingNavigator automatically generated, when i right click on the navigator and click on "view code",  the code behind it is:

        private void ordersBindingNavigatorSaveItem_Click(object sender, EventArgs e)
        {
            this.Validate();
            this.ordersBindingSource.EndEdit();
            this.ordersTableAdapter.Update(this.nORTHWNDDataSet.Orders);

        }

I have a few questions:

1, the line "this.Validate()"; what is it for do i need it if i want to have another button elsewhere on the form to update/remove/addNew data

2, it only shows the code of "saveItem_Click" event, what about others, e.g. "previous", "next", especially "Add New"   because instead of this nevigator, i want to build my own buttons to perform the same functionalities, reading the code will help me to learn. plz help me to find those code.