Thank you for contacting us.
Sorry, do you want to add more fields to class settings and show the field to the timetable?
If yes, you need to change a lot of source code to show that field on the timetable.
1. You need to edit the source code at file: /wp-content/plugins/noo-timetable/inc/post-types/add-meta-boxes/class-meta-boxes.php function add_meta_boxes() to add the field for class settings.
2. Then you need to edit the source code at file: /wp-content/plugins/noo-timetable/inc/post-types/noo_class.php to get the field data.