Nobody replied to this, but I finally worked it out myself. I couldn’t find how to add an image above the menu to my header, but managed to change the header colour. So for anyone else wondering the same thing here’s what I did.
Right click anywhere on your website and choose Inspect (Q)
Click on the arrow in the top left corner of Inspect
Then click on your header. This will tell you the “div class” of your header (mine is site-branding).
Exit Inspector by clicking the X on the far right.
To go your site’s dashboard.
Click on Appearance/Customise/Additional CSS
Input the following CSS:
/*header colour */
.site-branding {
background-color: #016eac;
}
Replace “.site-branding” with whatever your Inspect Q div class is for your header, and the hex (#) with whatever colour you want the header to be.
Click publish and your header colour should now have changed.
My theme is Twenty Seventeen.