大概會是
Private Sub CommandButton1_Click()
    
    Select Case True
        Case UserForm1.Frame1.Visible = False
            UserForm1.Frame1.Visible = True
        Case UserForm1.Frame2.Visible = False
            UserForm1.Frame2.Visible = True
        Case UserForm1.Frame3.Visible = False
            UserForm1.Frame3.Visible = True
        Case UserForm1.Frame4.Visible = False
            UserForm1.Frame4.Visible = True
        Case Else
    End Select
End Sub