Creating child theme

Hi,
I’m trying to create a child theme for twentythirteen, using Filezilla.

I took, as far as I’m aware, all the steps I needed to take according to the several tutorials I looked up.

The dashboard keeps saying the style.css doc is missing, and so the child theme isn’t active.
But I put the style.css there… I don’t know what I might do wrong anymore.

Is there anyone who can help me with this?

Thanks!