Getting links to child pages on the home main content area

I’m adapting the Education Base Pro theme to my own topic which is science.

I have several sub-topics and each of these have child pages. For example, Astronomy is a sub topic of the main “science” site and the moon is a child page under Astronomy. I have created both section IDs for vertical scrolling and a horizontal carousel. These sections list each of the sub topics, of which there are currently six.

What I am struggling to do here is to link into the child topics from the main content page. It seems you can add a single click button, but I need multiple. For example, under Astronomy there are pages for the moon, the planets, and eventually black holes, starts, galaxies, etc. I need to have links to each of these child pages. I can insert an image, but it doesn’t seem possible to link the image to a page.

I know I can add the Navigation menu or Categories widgets but these don’t seem to give me the option to insert a graphic and link it to a child page. Is my only option here to use the custom HTML widget for each sub-category?

Thanks!