How to add an automatic link in every thread in a particular forum

[reddyink]

I would like add automatic link in the tread only in a particular forum [id]

when someone adds a new thread, this link will automatically be put on the first line of the post in that forumdisplay.

Where is postbit? should I change and what exactly should I change?

how to do that?

[Lynne]

You can add it to the postbit (or postbit_legacy, depending on which one you use) template. Find where the message is displayed (should say $post[message] I think) and add above it:
<if condition="$thread['forumid']==x AND $post['postid']==$thread['firstpostid']">
your message written using proper html
</if>
Change x to the forumid you wish this to appear in.