Migrating Boot Disk...

Hi, I just bought the Alienware 17 R4. It's coming with a 128GB M.2 SSD + 1TB HDD Storage. 

I have a 512GB M.2 SSD and I want to use this as my new boot drive. Can I just install the 512GB SSD into the vacant M.2 slot and clone from the 128GB Boot Drive? Or do I need to do a clean install of Windows? Whats the easiest way? (FYI: I have not received the laptop yet so therefore have not even turned it on yet)

Thanks.