You got it right. “Order no” is the field where you have to put integer number (1, 2, 3 etc) of order. Same for the category screen:-
But as you said, question ordering is not working for you, do you have any caching plugin activated? If there is a caching plugin, please delete cache and deactivate caching plugin and check.
If you don’t have cache or the issue still exists, please create an admin account for us and send to us. While sending, make sure you check the box “Set as private reply” so that it will be hidden from everyone else. We will check the issue in your site.