This will flag comments for moderators to take action.
When you go into 'Edit Project Settings' you should see a form similar to the one you originally set your project up with, which has editable sections. I've added an image below to illustrate what you should be able to see. If you're either not seeing this, or you're still having trouble, you should try using WEbook in a different browser (Firefox, Chrome and Safari are recommended), and/or clearing your cache.
Failing all of that, email email@example.com and they'll get you some technical help.
Hannah from the WEbook Team