This page is available in Create Model Wizard in case you select the Import option on the first page of the wizard, which in its turn is available for NHibernate models only. This page allows you to import separately stored mapping.
Files for import
The list of files to be imported.
Add files
Click this button to add one or more files.
Add Folder
Click this button to add a folder containing the required files.
Remove
Click this button to remove unwanted files.