Logos in mastheads

Hi, I am just getting started with BL3 having been a long-time user of CE3 and CE4.
I am trying to understand how to put my logo at the very top of every page, just like the owners of this site do with TTG and BL3 logos. I have tried using the ‘substitute site name with logo’ option, but it always seems to put the logo under the site name, rather than replace it.
Any help appreciated.

you can use phplugins and custom css to replace the site title in the top pallet with an image logo.
see this example page:

Thanks Rod, didn’t realize that was a special function. I will humbly learn to walk first on this rev1 of my new site!