Using classes in a webpage

I copied this sample class and posted it inside of a website in a folder called APP_Code. The page is called class1.vb
I donot  understand Classes at all.
How do I use this on a webpage (like the index.aspx page)?
 
Imports Microsoft.VisualBasic
Imports System.Data
Imports System.Data.SqlClient
Imports System.Web.UI.WebControls
Imports System.Web.UI.Page
 
   
Public Class PersonName
    Inherits Page
    Public Sub New()
        _firstName = """"
        _lastName = """"
 
    End Sub
    Public Sub New(ByVal firstName As String, ByVal LastName As String)
        _firstNa ...