1. You can move blocks around if you choose.
2. The New Item block (Im assuming you mean in the Navigation Menu Builder) is meant for adding options within/on your main menu bar for pages that you have added. So if you create a new page, you would also want to create a New Item in the navigation menu builder so that your members could access it.
3. There are several things that are in the Edit Item that you want to pay attention to:
- System Name (how the 'system' will recognize the item)
- Language Key (the language key associated with the item)
- Default Name (The title/name of the item)
- URL (location of this new item)