Custom Post Types pagination

Hello,

I am trying to add pagination to a Custom Post Type that I have called casestudies. So far I have created the CPT and some sample content. In functions.php, I created a shortcode as follows which shows all the posts:

function show_custom_casestudy_all_pagination_callbk(){
    ob_start();
    global $post;
    $args = array(
                  'post_type' => 'casestudies',
				  'post_status' => 'publish',
				  'posts_per_page' => -1,
				  'caller_get_posts'=> 1
                  );

    $query = new WP_Query($args);

    if($query->have_posts()):while($query->have_posts()):$query->the_post();

    echo '<div class="casestudy-container">';

    echo '<div class="single-casestudy">';

    echo '<h2 class="case-title">'.get_the_title().'</h2>';

    $odmname = get_field('odm_name',$post->ID);

    if( $odmname ) {

    echo '<p class="odm-name"> ODM Name :- '.$odmname.'</p>';

    }

    $odmemail = get_field('odm_email',$post->ID);

    if( $odmemail ) {

    echo '<p class="odm-mail"> ODM Mail :- '.$odmemail.'</p>';

    }

    echo '<div>';

    echo '</div>';

    endwhile;endif;

    wp_reset_postdata();

    return ob_get_clean();

}

How do I get it to now show only 2 posts at a time and then put pagination / pager at the bottom?

Thanks….