$post_ids=array(100,200,300,400,500,600,700,800,900,1000);
$orderby_post_ids = array(300,800,500);
//$order=Ascending/ Descending;

$args = array(
        'post_type' => 'mycourses',
        'posts_per_page' => 4,
       'orderby' => 'post__in',
       'order' => 'ASC',
       'post__in' => $post_ids,
    );