Guys pls need your guide on how to add extension to a website.e.g www.mysitename.com/extension

Do i need to register the extension with a domain register pls kindly explain the step from Cpanel to Add on Domain....
tnks

There are two ways to achieve this..
Logon to ur hosting cpanel scroll down locate the subdomain tab, click it, imput the extension i.e shop. In this case to access this u will have to type something like shop.yourdomain.com
2. You may want to upload the extension folder to your domain e.g upload the folder directly into your domain name filezillah is good for dis, in dis case 2 access d folder u will have 2 type somethin like yourdomain.com/forum or d extension folder name. More help? Let me know..