Styles.css is not on the local disk. (dreamweaver cc 2017)

Just geting started learning dreamweaver and doing a simple tutorial.  Following the instructions and getting this error message.  I will attach some images.

When I add images to the site, they appear in the design mode but not the live mode.  Any ideas of what I am doing wrong?

I have done some other hidden file deletions and have reinstalled the software and it continues to do this. Any thoughts welcome.

I am on a mac running Sierra 10.12.5