If you are looking for defined location, use:
FormStartPosition Enum (System.Windows.Forms) | Microsoft Docs[
^]
One of the enum is
manual[
^] for a point location:
Public Sub New()
InitializeComponent()
Me.StartPosition = FormStartPosition.Manual
Me.Location = New Point(0, 0)
End Sub
About child-parent communication, you can use multiple ways - callback, delegates, properties.