Left click the user's name on the left side of a post. A pop window come up, one option is to start a conversation. I'll find a post from niente and post it here, so you'll have something to click on
https://forums.daybreakgames.com/eq/index.php?threads/missing-characters.268293/#post-3939173 That post is from Niente. Click to that post, and then click his name and off you go! PS - if you didn't know, there's a top level forum called STAFF TRACKER. That's where I found something so quick