Setting up new theme: Navigation bars and tabs.

Hello

I have changed my theme recently, and cannot figure something out even after google searching documentation. If you compare the two links, I want to EDIT the “navigation” bars on the top and bottom of the header. I can’t figure out how this is done. If you compare the two links, you’ll see the issue.

This is the template.

https://www.elegantthemes.com/preview/CherryTruffle/

This is my site. I want to change the “tabs” to link to particular pages that are on the site. Right now, I have nothing to link to them with.

https://www.practicalphilosophy.net/

Thank you in advance.