How to display my Nickname in the forum

Y'all seem to have solved this issue already, hence I am asking everybody: Most of you in this forum use their Nickname, the name under which they offer pix etc. Which makes sense as this is the name under which we are known in the stock world. For some frickin' reason I am posting here under my "real" name, not my nick, which makes perfectly zero sense. Could you guys share with me how to post under my nick, please?