Loading external booking plugin

I’ve created a new custom link menu item ‘Book Online’ and included the # within the url field.

I’ve then put in the the code below in to the JinMenu area for the same menu item and it doesn’t do anything. My code I am trying to run is below:

data-he-id=”xxxxxxx” src=”https://healthengine.com.au/webplugin/appointments.js”

Is there a different way that I should be calling the script? Something else I’m doing wrong?