Board Thread:Support Requests - Getting Technical/@comment-25021327-20150812122325

Hello all, I'm just wondering how I would go about adding a new notice to the editor on the WIki where I'm an admin. I'd like to have a small message appear whenever someone reates a page reminding them to check the rules before posting. I have seen this done over at the Creepypasta Wiki

https://i.gyazo.com/20fc332aa3488a35ee072005907480ed.png

It seems like a simple thing to do, but I'm not exactly sure how to get to where I could add or edit it. Any help would be apreciated :) 