Pages without a proper title will be listed as "New Page" in the table of contents. The table of contents will automatically list the text added to the default title text box. There is a default title text box at the top of every new page. See the image below.
After adding a title to your page, the table of contents will update to display the new title. You can use the text boxes from the text tab to add additional stories, captions, etc. to the new page. This way, all the text on the page doesn't also get added to the table of contents.
You can also change the "New Page" title in the Settings panel of the page editor. This is helpful if you do not wish to add a title to the page or if you have deleted the default text box for the title.
Navigate to the page that is titled "New Page" in the editor
Select the Settings panel
Beneath the Table of Contents section, deselect "Use the default page title"
Click in the "Page caption" box to type your page title.
You can also opt to exclude the page from the table of contents. Deselect "Include this page" in the Settings panel.