how to show all post in my page-grid.php template page

<?php

$args = array(
'post_type' => 'put your custom PostType name here',
'posts_per_page' => '-1'
);


$query = new WP_Query( $args );


if ( $query->have_posts() ) {


    while ( $query->have_posts() ) {

        $query->the_post();

        // Contents of the queried post results go here.

    }

}

// Restore original post data.
wp_reset_postdata();

?>