Fluent Forms : Number field with buttons

ff-numeric-addon-bttns.php

/*
* Fluent Form : Creating a Number field with + / - Button embeded with the input field
* Take a Numeric Field then add element class 'incremental-input', thats it
*/
add_filter('fluentform/rendering_field_data_input_number', function ($data) {
    if ($data['attributes']['class'] == 'incremental-input') {
        $data['settings']['prefix_label'] = '<button class="ff-btn-step-plus">+</button>';
        $data['settings']['suffix_label'] = '<button class="ff-btn-step-minus">-</button>';
    }
    return $data;
});

add_action('wp_footer', function () {
    ?>
    <script>
        jQuery(document).ready(function ($) {
            $('.ff-btn-step-plus, .ff-btn-step-minus').click(function (e) {
                e.preventDefault();
                const inputField = $(this).closest('.ff_input-group').find('input[type="number"]');

                if (inputField.length) {
                    let currentValue = parseFloat(inputField.val()) || 0;

                    if ($(this).hasClass('ff-btn-step-plus')) {
                        currentValue += 1;
                    } else if ($(this).hasClass('ff-btn-step-minus')) {
                        currentValue -= 1;
                    }

                    inputField.val(currentValue);
                }
            });
        });
    </script>
    <?php
});

Hello! Thanks for sharing this script. I have a really newbie question - may I know where should this script be uploaded to? Is it to the root Wordpress directory? Thank you!