How to redirect a subdomain or make subdomain available using visual studio

My question is where do i paste the code shown below in order to make subdomain available on net. is it the web configuration file or the new website configuration file.
Another question is what is the default document on your document root.

How to redirect a subdomain to a subdirectory
For example:

http://subdomain1.YourHostedDomainName.com --> http://subdomain1.YourHostedDomainName.com/subdomain1
http://subdomain2.YourHostedDomainName.com --> http://subdomain2.YourHostedDomainName.com/subdomain2
http://subdomain3.YourHostedDomainName.com --> http://subdomain3.YourHostedDomainName.com/subdomain3/home.asp

The following is a sample script that you can use to redirect a subdomain. You will need to place it as default document on your document root.

<%
If InStr( UCase(Request.ServerVariables("SERVER_NAME")), UCase("subdomain1.YourHostedDomainName.com") ) > 0 Then
Response.Redirect("/subdomain1")
ElseIf InStr( UCase(Request.ServerVariables("SERVER_NAME")), UCase("subdomain2.YourHostedDomainName.com") ) > 0 Then
Response.Redirect("/subdomain2")
ElseIf InStr( UCase(Request.ServerVariables("SERVER_NAME")), UCase("subdomain3.YourHostedDomainName.com") ) > 0 Then
Response.Redirect("/subdomain3/home.asp")
End If
%>

 

Example

Please, i want u to give me example

 

...What technology would you like the example for?
i.e. Classic ASP, ASP.NET, etc.