sub-web/sub domain

[Gus]

I already have a web-site. How do I create a sup-domain and make it work?
I've already created the sub-domain on the web host. I also created a new
WEB with the same name as the sub-domain. My original web uses index.htm.
what triggers the sub domain?

Hope this makes sense.
Thanks

 

[Gus]

I figured it out!
I kept typing www in front of the sub-domain name. It loads without the
WWW....
Thanks anyway...