Header

Hello team, I want to make a website for a non profit club without sufficient money to pay for it. That is why I choose to work with the free template elevatbiz. However I encounter some serious problems when I want to make the header. Wat I should like is a simple header, with in one row the site logo and the navigation (only pages not socials etc.) And underneath this a small image over the entire width. I trued for hours to realize this, but I failed. Is there someone who can Gove me a set of clues so that I can realize this header. I want to use the samen header for as well the front page as the other pages. Thank you in advance. Kind regards Hans Hagmeijer