Create a custom search form

I am thinking of creating a custom search form, which searches both in regular post types/fields and in custom post types/fields created with MB. I would like to test this code: https://awhitepixel.com/blog/wordpress-how-to-create-custom-advanced-search-template/

Will this kind of code work with MB post types and fields? And even if the data is stored in an custom table? I am especially thinking about this part of the code:

if (!empty($author)) {
    $meta_query[] = [
        'key' => 'book_author',
        'value' => $author,
        'compare' => 'LIKE'
    ];
}

Do you have any suggestions?