Returning Function in VB.net

I have a problem in this code because I am not returning any thing!

It works Just as I want it without returning but when I return it crashes.

Can you please help?

Public Function Clear() As Boolean


    'resetting the variuabels to be ready for next Order


    ZYZZ = "0"
    VAT = "0"
    MAX = "0"

    'this code is 3 peices 

    'This is sitting ctrl as a new control
    Dim ctrl As Control = Me.GetNextControl(Me, True)



    '1- is to look for text box and change them to 0 after the button is pressed
    Do
        If TypeOf ctrl Is TextBox Then
            ctrl.Text = "0"
        End If
        ctrl = Me.GetNextControl(ctrl, True)

    Loop Until ctrl Is Nothing


    '2- it clears the list box
    OrderListBox.Items.Clear()

    'And uncheck the check boxes
    LoyalCheckBox.Checked = False
    TakeAwayCheckBox.Checked = False


    'Finally it resets the Price, VAT, Total in the UI 

    Label6.Text = "£" & " " & "0"
    Label7.Text = "£" & " " & "0"
    Label8.Text = "£" & " " & "0"

    'Clearing the array to prepare for next order

    arr.Clear()



End Function

Also same problem in this code!

Private Function calculate() As Boolean


    '=================================='

    ZYZZ = 0

    For i As Integer = 0 To arr.Count - 1

        ZYZZ = ZYZZ + arr(i)

    Next i

    '=================================='


    '=================================='

    If LoyalCheckBox.Checked = True Then

        CardT = ZYZZ * card

    Else
        CardT = "0"

    End If

    If TakeAwayCheckBox.Checked = True Then

        TAF = ZYZZ * TA


    Else
        TAF = "0"
    End If

    '=================================='

    VAT = ZYZZ * cVAT

    MAX = ZYZZ - (CardT + TAF) + VAT


    Label6.Text = "£" & " " & ZYZZ

    Label7.Text = "£" & " " & VAT

    Label8.Text = "£" & " " & MAX



End Function

I have looked up online but I did not understand the methods they are using that's why its better to ask a direct question, thank you.