I have found no way to answer a question that was posted even though I am signed in. Did I forget something vital???

Hi Bk,

Down the bottom of the page you'll see a "Post reply to" box with a green header on it. It will be almost the same as the one you typed your question into. Enter you reply to the question or thread that you want to contribute to there and click "Finished".

Hope that helps!

Kind Regards,
Joshua.

Scroll down the page.
You will see a colored line with white writing that says: "Post a reply to..".
Beneath the colored line is a blank box in which to write your message.
When you have written your message, send it by clicking on the green "Finished" button below the message box.

I cross-posted with @Australis !

@QueenEmma
What she may not understand is that if you want to reply with a specific answer to a specific person you can't do it directly. You can summon the person by using the at symbol @. I used it for this reply to you, use the symbol followed by the person's user name.

Good point, Larry. Hadn't thought of that.

It also won't work if you don't add a space in front of the @ sign. I had the hardest time figuring that out when I first tried it.

She got the answer in this thread and did reply:
The thread "Re- learning how to get into site please" in Ask a Question forum