Need help again (I need to start asking in the middle of the week).

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"Code the Add button's Click event procedure so that it adds the amounts entered by the user to an accumulator variable and then displays the variable's value in the lblSales control. Use an arithmetic assignment operator to update the acumulator. Display the total sales with a dollar sign and two decimal places."

The other one I need help with.

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Public Class frmMain

Private Sub btnExit_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnExit.Click
Me.Close()
End Sub

Private Sub btnClickMe_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnClickMe.Click
' blinks the message in the lblMessage control

' declare counter variable
Dim intCount As Integer

' begin counting
intCount = 1
Do While intCount <= 20
If lblMessage.Visible = False Then
lblMessage.Visible = True
Else
lblMessage.Visible = False
End If
Me.Refresh()
System.Threading.Thread.Sleep(250)
' update the counter variable
intCount = intCount + 1
Loop
End Sub
End Class

"Change the pretest loop in the btnClickMe control's Click event procedure to a posttest loop that uses the Until keyword."

A step-by-step guide would be preferable, if possible.