This article will help you better understand the process of creating multiple sites using multi-domains.Let’s say, you want to run multi sites using domains such as domain1, domain2, and domain3. The website is the top-level container for sites, shipping methods, payment methods, and so on.Each website and each store view must have a unique identifier. The store is contained in a website. In turn, a store contains at least one store view.
Goto Admin > System > Configuration > Manage Stores > Create Website
Fill the Website information
Goto Admin > System > Configuration > Manage Stores > Create Store
Fill the Store information
Goto Admin > System > Configuration > Manage Stores > Create Store View
Fill the Store View information
You need to complete the store creation is to configure its settings through the configuration of your Magento.
Goto Admin > System > Configuration > Current Configuration Scope
Goto Admin > System > Configuration > Current Configuration Scope > select the Website that you created > Web > Type Base URL for your store under Unsecure and Secure section.