Set of posts for the front page

You can develop a theme settings page, or better yet, a customizer section, that allows users to select or indicate the desired posts. Your front page template code would then query for the selected posts and output the grid content.

How you want users to select posts is up to you. Something like how pages can be selected to be linked to as menu items on the menus admin screen is one model. A series of fields where users paste in URLs will work.
https://developer.www.ads-software.com/themes/customize-api/

OK. Thanks. Will set up a customiser section.

I was busy elsewhere and picked it up yesterday. I’m having problems adding a panel/section to the customizer file of the underscores starter theme. I’ve read the customizer section of the official documentation but cannot get anything to work or appear in the customizer dashboard.

My addition is this bit:

 $wp_customize->add_panel( 'front', array(
        'title' => __( 'Front', 'Solar' ),
        'description' => 'my description', // Include html tags such as <p>.
        'priority' => 160, // Mixed with top-level-section hierarchy.
    ) );
    $wp_customize->add_section( 'front_section' , array(
        'title' => __('Footer_section', 'Solar'),
        'panel' => 'front',
    ) );

A whole customizer file is as follows:

<?php
/**
 * Solar Theme Customizer
 *
 * @package Solar
 */

/**
 * Add postMessage support for site title and description for the Theme Customizer.
 *
 * @param WP_Customize_Manager $wp_customize Theme Customizer object.
 */
function Solar_customize_register( $wp_customize ) {
	$wp_customize->get_setting( 'blogname' )->transport         = 'postMessage';
	$wp_customize->get_setting( 'blogdescription' )->transport  = 'postMessage';
	$wp_customize->get_setting( 'header_textcolor' )->transport = 'postMessage';

    $wp_customize->add_panel( 'front', array(
        'title' => __( 'Front', 'Solar' ),
        'description' => 'my description', // Include html tags such as <p>.
        'priority' => 160, // Mixed with top-level-section hierarchy.
    ) );
    $wp_customize->add_section( 'front_section' , array(
        'title' => __('Footer_section', 'Solar'),
        'panel' => 'front',
    ) );

	if ( isset( $wp_customize->selective_refresh ) ) {
		$wp_customize->selective_refresh->add_partial(
			'blogname',
			array(
				'selector'        => '.site-title a',
				'render_callback' => 'Solar_customize_partial_blogname',
			)
		);
		$wp_customize->selective_refresh->add_partial(
			'blogdescription',
			array(
				'selector'        => '.site-description',
				'render_callback' => 'Solar_customize_partial_blogdescription',
			)
		);
	}
}
add_action( 'customize_register', 'Solar_customize_register' );

/**
 * Render the site title for the selective refresh partial.
 *
 * @return void
 */
function Solar_customize_partial_blogname() {
	bloginfo( 'name' );
}

/**
 * Render the site tagline for the selective refresh partial.
 *
 * @return void
 */
function Solar_customize_partial_blogdescription() {
	bloginfo( 'description' );
}

/**
 * Binds JS handlers to make Theme Customizer preview reload changes asynchronously.
 */
function Solar_customize_preview_js() {
	wp_enqueue_script( 'Solar-customizer', get_template_directory_uri() . '/js/customizer.js', array( 'customize-preview' ), _S_VERSION, true );
}
add_action( 'customize_preview_init', 'Solar_customize_preview_js' );

I just want to add a new panel/section with a text input field.