Please add the following code in your child theme functions.php or in youe wp-content/plugins/wplms-customizer/wplms-customizer.php :

  

add_filter('wplms_course_credits_array','customwplms_course_credits_array',10,2);
function customwplms_course_credits_array($credits,$id){
    $flag = 0;
    $new_credits = array();
   if ( in_array( 'paid-memberships-pro/paid-memberships-pro.php', apply_filters( 'active_plugins', get_option( 'active_plugins' ) ) ) ) {
            $membership_ids = vibe_sanitize(get_post_meta($id,'vibe_pmpro_membership',false));
            $match = array();
            if(isset($membership_ids) && is_Array($membership_ids) && count($membership_ids) && function_exists('pmpro_getAllLevels')){
             $link=get_option('pmpro_levels_page_id');
             $link=get_permalink($link);
             foreach($membership_ids as $membership_id){
                $match[]=$link.'#'.$membership_id;
             }
             
             foreach($credits as $key => $value){
                if(in_array($key,$match)){
                    $flag=1;
                    $new_credits['http://google.com'] = $value;
                }else{
                    $new_credits[$key] = $value;
                }
             }

        }
    }
    if($flag)
        $credits = $new_credits;

    return $credits;
}

 
Note: In the above code you can add your custom link by replacing the "http://google.com