Implementing header menu?

This is a lovely theme, thank you so much for making it available.

The only problem I’ve encountered is that I can’t seem to find a way to enable a navigation menu in the header. In the sample of the theme I can see several page links in the top header bar, but in my implementation those don’t appear, and there’s nothing related to the header that’s available to configure in either widgets or menus.

What I’m trying to accomplish is to have the blog be the default page (as it is now), but have the three pages on my site (About, Contact, Resources) available in the top navigation bar.

I’m willing to create a child theme and edit the templates if necessary, but I’m hoping there’s an easier way to do it ??

Many thanks in advance for any help you can offer.

(Oh, the URL is https://mamamusings.net/dubrovnik/ )