Journal is a free, 100% responsive, simple and unique blogger theme specially designed for writers. Journal Blogger template has a minimal and clean style and it is visually pleasing and easy to read. Also it has a overlay responsive menu, overlay search field, web fonts, auto post summaries, share buttons, related posts with thumbnails, 2 columns footer and more.
How To Change Header Image
Find this in "Edit HTML":
https://4.bp.blogspot.com/-MLWdX8GZCrs/WZRh_LoZcvI/AAAAAAAASAk/UtrxERcb8YUU59N6ePSbBPcQQWB0ron5ACLcBGAs/s1600/head.jpg
Replace it with your own header image URL.
How To Add Links to Navigation Menu
Go to "Layout". Click on "Edit" link of "Edit This Menu" widget.
Now add your links to that link list widget.
https://newbloggerthemes.com/blog/how-to-configure-linklist-menu-widget/