As usual we start with the API declaration.

Create a new VB Standard EXE project.

When you created the project, a form Form1 should have been added to the project by default. Add another form to the project. Since this is only an example to illustrate the above API call, we'll not change the properties of the forms. So now we have two forms named Form1 and Form2 in the project. Add a command button each to both the forms. Leave their names as Command1 itself.

In the General | Declarations section of both the forms, type in the following code

Private Declare Function BringWindowToTop Lib "user32" Alias "BringWindowToTop" (ByVal hwnd As Long) As Long

In the Click event procedure of the button on Form1 add the following code:

Private Sub Command1_Click ()
   BringWindowToTop Form2.hwnd
End Sub

In the Click event procedure of the button on Form2 add the following code:

Private Sub Command1_Click ()
   BringWindowToTop Form1.hwnd
End Sub

Now in the load event of Form1 (which should be the default form of the project add the following code.

Private Sub Form_Load ()
Form2.Show
End Sub