How do I comment or add to a previously asked question?

[SOT3]

First, you must switch to desktop mode.

As to responding to answers, you don't directly. YA is not a chat room or Facebook. You have two options:

1. E-mail or IM the user through their profile.

2. Wait until you pick the BA and add comments for each user. Probably only the Best Answer will see it since they only get a notification.

The ONLY exception is that you can add additional details to your question for clarification of the question. Do not call users by name doing this or it will be deemed chat. This options seems to fit your situation.