More detailed instruction:

Unfortunately the attachment icon doesn't work at the moment. So,... instead click on Go Advanced (below the Edit Window) while composing your reply, then scroll down to and click on Manage Attachments and the Upload window will open. Click on Browse and navigate to (and double-click) the file icon that you want to attach, then click on Upload and then on Close this Window to return to the Edit window. When you have finished composing your post, click on Submit Post.

Make sure confidential information is removed first!!!!