Visual Basic code- Having trouble displaying the Total. New to VB - vb.net

Question

I have to write a program that calculates costs for a catering company. i have that part down, but whats stumping me is I have trouble displaying the total. What also is stumping me is that i have to make a summary button that adds everything up into a grand total from the previous calculations and display it in a message box. displaying and calculations aren't really my issues, but getting the data to calculate is.
Thank you
HERE's the code.
Const decPRIME_RIB As Decimal = 25.95D
Const decCHICKEN As Decimal = 18.95D
Const decPASTA As Decimal = 12.95D
Const decOPEN_BAR As Decimal = 25D
Const decWINE As Decimal = 8D
Const decBEER As Decimal = 10D
'Declare module-level variables for summary information.
Private TotalDollar As Decimal
Private AmountDue As Decimal
Private SubTotalDecimal As Decimal
Private TotalDecimal As Decimal
Private Guest As Integer
Private EventCountInteger As Integer
Private Sub CalcBtn_Click(sender As Object, e As EventArgs) Handles CalcBtn.Click
' Calculate and display the current amounts and add to totals.
Dim FoodChoiceDecimal As Decimal
Dim OpenBarDecimal As Decimal
Dim WineDecimal As Decimal
Dim DrinksDecimal As Decimal
' Find the price.
If PrimeRB.Checked Then
FoodChoiceDecimal = decPRIME_RIB
ElseIf ChickRB.Checked Then
FoodChoiceDecimal = decCHICKEN
ElseIf PastaRB.Checked Then
FoodChoiceDecimal = decPASTA
End If
If OpenCB.Checked Then
OpenBarDecimal = decOPEN_BAR
End If
If WineCB.Checked Then
WineDecimal = decWINE
End If
'Multiply price by number of guest and drink selection.
Try
DrinksDecimal = (OpenBarDecimal + WineDecimal)
AmountDue = (FoodChoiceDecimal + DrinksDecimal) * Guest
' display totals.
TotalLbl.Text = TotalLbl.ToString("C")
' Allow change for new event.
OpenCB.Enabled = False
WineCB.Enabled = False
ClearBtn.Enabled = True
SummaryBtn.Enabled = True
Catch NumberOfGuestsException As FormatException
MessageBox.Show("Number of Guests must be Numeric", _
"Data entry Error", MessageBoxButtons.OK, _
MessageBoxIcon.Information)
End Try
End Sub
Private Sub SummaryBtn_Click(sender As Object, e As EventArgs) Handles SummaryBtn.Click
' Calculate total dollar amounts and number of events.
Dim MessageString As String
If EventCountInteger > 0 Then
' Calculate the summary sales totals.
TotalDollar += AmountDue
'Concatenate the message string.
MessageString = "Number of Events:" & EventCountInteger.ToString() _
& Environment.NewLine & Environment.NewLine _
& "Total Sales: " & TotalDollar.ToString("C")
MessageBox.Show(MessageString, "Sales Summary", _
MessageBoxButtons.OK, MessageBoxIcon.Information)
End If