Branford Magazine Header

I am a newbie and am trying to see if I can add another image to the Header. I feel like I’m going crazy because when I look up how to do this all the info says to go to Header under the Appearance menu and I do not have a Header section under the Appearance menu. I was thinking maybe I’d have to do something on the Header template but am scared to mess around in there if I’m not exactly sure what I’m doing.
Any help or advice would be greatly appreciated.