Smartthing alerts with Pushover Manager?

Hi - as I don’t live in the US i can’t get Smartthings to text me when one of my sensors is triggered. As such I have installed a new smart app called ‘pushover manager’ which I believe should help me get some alerts. However, having now installed it correctly, I’m not sure how to actually configure it/ trigger it when a sensor is activated. Does anyone know of a simple guide I can follow?