Can't find Theme to edit it

Update ... Found it

Hi
Very, very new to this, managed to download Atahualpa at the weekend and have great fun using it. I was trying to change the logo at the top left, for my own, and last night found it in filezilla? (sorry, I said I was new!) managed to get my own logo in there .. changed format, drag and drop etc .. but it didn't show on the site. I left it until today and did other stuff but hate to be beaten so came back .. now I can't find any reference to Atahulapa in Filezilla .. my site is fine, I think! so where has it gone and how do I get it back to have another go at editing the logo? Thank you and sorry to be dim .. Bec