How can I modify the navbar in the Casper theme?

Hi, I’m a new Ghost user and I liked the look of Casper for my website. The only problems I had with it so far are with the navbar. I’d like to remove the ‘About’ button and replace it with something else or hide it. I downloaded the theme from the settings and couldn’t find anything related to ‘About’ in the code.

Under Settings, go to navigation! (Right next to the design link you used to download the theme.)

Thank you, is it possible to remove this search button as well?