External URL Redirect passing user role as query params

I was able to implement a custom screen with an action button that when clicked, it open an external url which is basically a UI which works with the acumatica RestApi and perform specific actions and AI analysis on it. It working perfectly. But I want to try something else, to reduce the delay - in fact the user has to click on the button to open the web application inside acumatica frame. I want to execute 2 actions: 

2.   when I open the custom screen it automatically loads trigger the URL redirection and load the web application.
3.  to pass the user role in the query : “http://webapplication.com?role=’role of the user’