Sorry for the late reply.
So, you first need to create a 1x1 (pixel) transparent image.
If you can't do it, here's a link that includes it : sta.sh/0u1i1px1zpj
Once you download/create the image, post it on deviantart. Name it however you'd like. I recommend disabling the comments, but it depends on you.
Then, once finished posting, place it is the featured deviation.
And then you're done.
If you're still confused, please tell me.