Honeywell Lynx alarm trigger output into smartthings

Hi all,
I’m new to the forum so hello!
I have a Honeywell Lynx L5100 and st v2, the Lynx looks after security the st does everything else.
I am looking for some help on how to physically connect the trigger output from the 5100 to something that can be monitored by st. I have seen posts that it can be done but none that explain how.
My aim is to have st know if the 5100 alarm has activated - assumed this was the easiest solution.

Any help would be appreciated…