Best Pratice Newbie Question Regarding Custom Classes

I'm a newbie programmer so this might be a bit of a no-brainer for you experts, but I'm just looking for some guidence in regards to custom classes.

I created a class file called shipping.vb that lives in my App_Code folder

The Namespace in the shipping.vb file is called:
MyCompany.ProgramMnagement.DataLayer

I also have a public class within that namespace called 'shipping' and a function called 'InsertShippingRecord'.

In my code behind I do something like this to instantiate my class and use that function.

Dim myShippingClass As New MyCompany.ProgramManagement.DataLayer.Shipping()

I then write the following to utilize the InsertShippingRecord function of my shipping class:

Dim insertNewShippingRecord As Int32 = myShippingClass.InsertShippingRecord()

This all works perfectly.  No problems.

My quesiton is... is this the best way to do it?  

The other night I was thinking that maybe I could import the class, similar to the way I import System.Data.SqlClient at the top of my code behind page.  It sounded like a good idea but I'm not sure.

Any feedback would be greatly appriciated.