All Pages visible on the Frontpage

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In Twenty Seventeen you can only add 4 page in front-page section. see image below

enter image description here

See Appearance=> Customize => Theme Options

Update

You can add extra section with filter twentyseventeen_front_page_sections add this code in functions.php

function tws_custom_front_sections( $num_sections )
    {
        return 5; //Change this number to change the number of the sections.
    }
add_filter( 'twentyseventeen_front_page_sections', 'tws_custom_front_sections' );