"Virtual hosting" means hosting multiple websites with different domain names on the same IP address.
From the "Internet Information Services (IIS) Manager" window, right-click on a website, and select "Edit Bindings...":
In the "Site Bindings" dialog, select the first item and click the "Edit" button:
Enter the website domain name in the "Host name" field:
Click the OK button in all the dialogs to save your changes.
Create additional websites the same way.