Add an additional section to Front-Page

Hi everyone,

I am using a child version of TwentSeventeen for this site. Now I want to add another section in the Homepage. I tried to edit the front-page.php file, where I found the number of the sections

$num_sections = apply_filters( 'twentyseventeen_front_page_sections', 4 );

and if I put a lower number sections don’t show in Homepage, but if the number is higher I think I have to add also the controls on the Theme Options of the Customizer to choose the page that will be added as a new section.

How can I get another control for the fifth section on the Customizer?
Maybe need I to add something in the functions.php file?

Thank you for your attention!
Ab

The page I need help with: [log in to see the link]