That code I pasted refers to the 'dialogID' within it. You can find that number by selecting the conversation on the left side of the editor in the game objects list. When the conversation name opens, hover the mouse over the upper right side of the screen, and a number magically appears. like 79278... place that number so it replaces the text of 'dialogID' in the code like this:
<script type="text/javascript">
var ARIS = {};
ARIS.ready = function() {
ARIS.exitToDialog(79278);
}
</script>
When this plaque is activated after being unlocked by 'the player viewing the plaque' previous, it sends the player to the conversation right away, they won't even see this plaque with the code in it. You could call this plaque 'Send to Conversation XXX' so you can identify it in the editor.
You don't really have to understand how the javascript works to use the ARISjs except where to find the numbers if needed for plaque IDs, conversation IDs, etc.
I used this reference a lot when first programming with ARIS.
https://sites.google.com/site/aris2manual/editor/arisjs