XF 1.1 How do I?

[JpA]

How do I get like this green box with my own custom message in it on the top of my page?

http://puu.sh/5DfFn.png

Another website has it too like this:

http://puu.sh/5DfO5.png

 

[Andrej]

http://xenforo.com/help/notices/