How do I install new Mac OS onto a new unformatted HD
The MacBook 13" Mid 2007 is obsolete!  Meaning that even with the latest version of Mac OS X it supports, 10.7.5, the OS is no longer supported in any respect, has un-patched security flaws that will never be fixed. From a security standpoint, you'd be better off running a current version of Linux Mint then Mac OS X Lion 10.7.5 on that MacBook.

That said, if you really want to run the latest Mac OS X that MacBook model supports, then you'll need to acquire a copy of the Install Mac OS X Lion.app application bundle and use DiskMaker X (formerly Lion DiskMaker) to create the USB Installer as it does not support the createinstallmedia command found in the application bundles of the OS X installers starting with OS X Mavericks and later.

If you previously purchased Mac OS X Lion, then I believe it should appear under Purchased in the App Store and can be downloaded again and if not then you'll have to ask a friend to see if it's in theirs. 

Another possible option is to take the MacBook to an Apple Store and see if the Genius Bar can install a copy of Mac OS X Lion for you.