Accumulate Test Score Data

I have been working on a class project for sometime now. Currently stuck and need some help. Project is due today, so I'm desperate for some help. Please see attached project file. Any help will be appreciated.

My code so far

Code:

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Public Class Form1

    Private Sub btnExit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnExit.Click
        End
    End Sub
    Dim lNumbers As List(Of Integer) = New List(Of Integer)
    Dim highScore As Integer
    Dim Score As Integer
    Dim totalScore As Integer
    Dim numberScores As Integer
    Dim averageScore As Decimal

    Private Sub btnAdd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnAdd.Click

        If TextBox1.Text >= 0 And TextBox1.Text <= 100 Then
            lNumbers.Add(TextBox1.Text)
            Score = TextBox1.Text
            totalScore = totalScore + Score
            numberScores = numberScores + 1
            lblScoreCount.Text = numberScores

            If (Score > highScore) Then
                highScore = Score
            End If

            lblScoreTotal.Text = totalScore
            averageScore = Math.Round(totalScore / numberScores, 2)
            lblAverage.Text = averageScore
       

    End Sub
End Class

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I cant get the message box to take my list to display a message with all of the numbers put in highest to lowest order and each number on a different line.

vb Code:

Private Sub btnDS_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDS.Click
        lNumbers.Sort()
        MessageBox.Show(lNumbers.Item(0).ToString + lNumbers.Item(1).ToString)
End Sub