Low storage on a brand new Lumia 550?

I'm too much of a novice to have downloaded anything yet so why is my three week old Lumia 550 showing low storage. First one was faulty and this second one when taken back to the store and checked was OK and I was told to ignore the low storage message?

Hi and welcome to AndroidCentral.

The Lumia 550 isn't an Android device. It's a Windows 10 Mobile device.

Please see our sister site WindowsCentral. http://forums.windowscentral.com/ask-question/

The Windows 10 Mobile experts there will be able to assist you.