Replies to a topic are called "postings".
If you want to create a posting, proceed as follows:
(1) Click on the title of the topic or posting to which you want to reply.
(2) An input mask appears at the bottom of the page.
(3) Enter a title and a text.
(4) Click on "preview >>" to check your entry.
(5) A preview of your posting is generated:
(a) If you want to change anything, click on "edit.
(b) If you are satisfied with the preview, click on "publish".
The reply input mask is not displayed, if the display setting "all items full text" is activated.