example-config.php

<?php


/**
 * The configuration options for the Shoestrap Customizer
 */
function shoestrap_customizer_config() {

	$args = array(

		// Change the logo image. (URL)
		// If omitted, the default theme info will be displayed.
		// A good size for the logo is 250x50.
		'logo_image'   => get_template_directory_uri() . '/assets/img/logo.png',

		// The color of active menu items, help bullets etc.
		'color_active' => '#1abc9c',

		// Color used for secondary elements and desable/inactive controls
		'color_light'  => '#8cddcd',

		// Color used for button-set controls and other elements
		'color_select' => '#34495e',

		// Color used on slider controls and image selects
		'color_accent' => '#FF5740',

		// The generic background color.
		// You should choose a dark color here as we're using white for the text color.
		'color_back'   => '#222',

		// If Kirki is embedded in your theme, then you can use this line to specify its location.
		// This will be used to properly enqueue the necessary stylesheets and scripts.
		// If you are using kirki as a plugin then please delete this line.
		'url_path'     => get_template_directory_uri() . '/kirki/',

		// If you want to take advantage of the backround control's 'output',
		// then you'll have to specify the ID of your stylesheet here.
		// The "ID" of your stylesheet is its "handle" on the wp_enqueue_style() function.
		// http://codex.wordpress.org/Function_Reference/wp_enqueue_style
		'stylesheet_id' => 'shoestrap',

	);

	return $args;

}
add_filter( 'kirki/config', 'shoestrap_customizer_config' );

Where do I need create and install this page?