Custom dialog in NSI script

I am a new NSI user so may be asking the obvious. I created a simple script to install a Java program. I want to inserrt a popup in the script to warn users of JRE requirement. How can I do that. Please see attached image.

Note: I do not want to add automatic JRE detection or installation just want to show this warning.

Simplest Answer...

MessageBox MB_ICONINFORMATION "${Name} needs at least Java Runtime Environment$\n1.4.1 or Later versions. Be sure to have that installed!" 

Thanks for your suggestion. Its exactly what I needed.