I believe you may have already figured t his out by now, but for the benefit of anyone else reading the thread I’ll walk through it.
ecobee Routines SmartApp you have the options of triggering off of a Routine execution OR a Mode change (whichever works best for your situation).
From there, you get to choose what Program (Comfort Setting) on the Ecobee that you want to execute. In addition to Programs, I also include the option to simply
Resume Program, but you can also choose between Home, Sleep or Away (or a custom program if you have one setup).
So, the first thing you need to do is either automate the running of your Away Routine or manually executing it from within the app.
I’ll leave setting up Routines as a separate exercise for the reader as it is really outside the scope. :o)