New HDD The disk you inserted was not readable by this computer.

I've put my brand new 2.5" hybrid hard drive in an enclosure and get the following message: "The disk you inserted was not readable by this computer." and have been given the following 3 options: Initialize... / Ignore / Eject.

What does Initialize do and is the right option for me if I want to format and partition my hard drive?

All help appreciated. 🙂