There are two answers to my question. Do I have to reply individually or is there a way of entering a reply on the common screen that contains the question and answers?
You would have to see how to join Windows Central here in order to reply. You can reply individually, if you'll like.
In the thread, there's a button after quote on every post. Just tap that button to reply to more than one response and then tap "reply" after the last post.
Facebook
Twitter
Instagram