by Andrew Nicols.
Hi Sandareka,
Sorry for the delay in getting back to you.
The call to yui_module() needs to go into the PHP generating your page. This will load the file described by the name of the module - I'd advise reading http://docs.moodle.org/dev/YUI/Modules for a bit more background. The strings_for_js code goes in the same place as the yui_module() call.
You should also take a look at the JavaScript moodle-core-notification class located in lib/yui/src/notification/js/notification.js. Amongst other things, this defines a set of dialogues based on the YUI Panel module. These include M.core.alert, M.core.confirm, and M.core.dialogue.
Cheers,
Andrew