Which API is used to send/fetch data that will be displayed on the player?

http://xibo.org.uk/manual-tempel/api/

I’m exploring the above API options, but can’t seem find the one which is used to send/fetch data to the display. Can you please help out?

scheduleAdd - that will create a new scheduled event
scheduleEdit - that will edit existing event, so you can change the layout/campaign on it
changeLayout - that will change the layout on display / display group to the specified one

If you meant something else, please do let me know

Like say I have this display of my own. And I wanna get the data/xml to show stuff on it. I’d be calling an API method changeLayout? If not let me know which it is.