Merging two pages into one homepage

Your theme is dynamically loading a template part.

Look here:

   $home_layout = get_post_meta($id, 'home_layout', true) ? get_post_meta($id,'home_layout', true) : 'style1';
get_template_part( 'inc/templates/homepage/'.$home_layout );

Now look in your folder at inc/templates/homepage/ and you should see the various template parts.

Those templates parts are where you’ll want to add your new code (for the about page).