Hey again Joseph28,
This is exactly what you need to do. Simply add the following code right below the logo end in your header.php which is located in the root folder of your theme, check screenshot https://screencast.com/t/4fLId6xTgo.
<div class="header_ad">
Add your ad here.
</div>
As I mentioned above I’d advise on using child theme so you can avoid losing changes once you update the theme.
After that we can use header_ad class which we added to this div to position it in the header as mentioned in the post you linked so for start you’d want to add the following CSS:
.header_ad {
float: right;
}
This will push it to the right side of the header, depending on the size of the image we’ll probably have to add some margins as well, I can help you with that also if you could post link to your site once you’re done ??
Hope this helps ??
Cheers,
Bojan