Reset Users Course Progress LearnDash

gistfile1.txt

// REST Code
function oddc_learndash_delete_user_activity( $user_id ) {

  if( empty( $user_id ) )
    return false;

  global $wpdb; 
  $users = $wpdb->get_results( $wpdb->prepare( "SELECT activity_id FROM ". $wpdb->prefix ."learndash_user_activity WHERE user_id = %d ", $user_id ), ARRAY_A  );
  
  if( !empty( $users ) ) {
    foreach( $users as $user_activity ){
      if ( !empty( $user_activity['activity_id'] ) ) {
        $activity_id = $user_activity['activity_id'];
        
        $wpdb->delete( 
          $wpdb->prefix .'learndash_user_activity',
          array( 'activity_id' => $activity_id ),
          array( '%d' )
        );

        $wpdb->delete( 
          $wpdb->prefix .'learndash_user_activity_meta',
          array( 'activity_id' => $activity_id ),
          array( '%d' )
        );
      }
    }
  }
  
}

add_action( 'init', 'reset_course_status' );
function reset_course_status() {

//**************** Custom Work **********
// Fetch the users from the CSV
global $wpdb;

$users = $wpdb->get_results( $wpdb->prepare( "SELECT * FROM ". $wpdb->prefix ."users WHERE user_email like '%s' limit 300, 100 ", '%@penskeautomotive.com%' ),  ARRAY_A );
//$users = $wpdb->get_results( $wpdb->prepare( "SELECT ID FROM ". $wpdb->prefix ."users WHERE ID = %d ", 3077 ), ARRAY_A  );



$current_user_id = get_current_user_id();
  if( !empty( $users ) && $current_user_id == 4936 ) {
    // echo '<pre>';
    // print_r( $users );
    // exit;

    foreach( $users as $u_id ){

      echo $user_id = $u_id['ID'];
      echo '<br>';
      $user_meta =  get_user_meta( $user_id, '_sfwd-course_progress', true );
      // print_r( $user_meta );
      // exit;
      
      if( $user_meta ) {
        // Go through the all courses
        foreach( $user_meta as $u_course_id => $u_meta ){
          delete_user_meta( $user_id, 'course_completed_' . $u_course_id );
        }
        delete_user_meta( $user_id, '_sfwd-course_progress' );
        
        // Reset Quiz progress
        delete_user_meta( $user_id, '_sfwd-quizzes' );  
      }
      
      // Delete activity meta
      oddc_learndash_delete_user_activity( $user_id );
    }
    exit;
  }

}

please detail me .! learndash_delete_course_progress() function please help how is function are works please help with all the detailed

learndash_delete_quiz_progress() function please help how is function are works please help with all the detailed