on the html5default template there is a LATEST block already available to use. It pulls the date added from the database to show new products.
Simply enable that block on your home page layout.
You can easily change the Latest Products to whatever you want to label it - this is done within the language definitions.
Easiest way to find it is to type Latest in the search box on the admin panel and it will bring up all the places you can alter the wording.
You can change how many Latest (New) porducts are shown within the system > setting > general tab
