To setup multi-store
set up your hosting Cpanel
Set up two or more domains in your hosting service control panel. This is very important to make sure that the second domain is routed to the correct folder.
set up your AbanteCart admin panel
in AbanteCart admin go to System » Settings
click on Create New Store button
fill in the at least following fileds:
Store URL: Include the full URL to your store. Make sure to add '/' at the end. Example: http://www.second.yourdomain.com/store/
Starting from AbanteCart v1.1.0 you able to copy all setting from already created store. At least from your default store.
click Save button, the page will reload and you will be able to edit all other store settings.