Onetone Home Page Menu

Hi, I would like to ad a link to my Onetone Home Page Menu but cannot find anywhere to add it. Appearance/Menus or Customize/Menus display no Home Page Menu for editing.

I was going to add the link the php code perhaps but cannot find the file which builds the Home Page Menu. At present, all the links lead to Home Page Sections and I would like to put at least one link on the menu which leads inside the site, such as my Table of Contents page.

Can someone please inform me where or how to ad the link to my Home Page Menu? I do have two other custom menus created, one for vertical side menu and one for pages/posts pages. Thanks for any assist with this little thing.

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