Thread:Yami riku/@comment-24675428-20170711230519/@comment-25646419-20170712203548

Basically whichever user has at least admin status and whoever was most recently active will automatically post a greeting. The greeting given to anonymous users is taken from the MediaWiki:Welcome-message-wall-anon page. The greeting given to registered users is taken from the MediaWiki:Welcome-message-wall-user page.

So you may be a greeter, but you do not need to worry about setting anything up.