Hi Dennis,
Unfortunately there is no flow card that is triggered when the Ring Alarm enters the Alarm State as the Ring Alarm support in this app is currently limited to obtaining and setting the Alarm Mode. (Please not the terminology used is ambiguous, the Alarm Mode relates to the Disarmed, Home and Away Mode where the Alarm State relates to an active or inactive Alarm)
I can’t test this myself, but if you have a Ring Camera you could try to use the The generic alarm turned on flow card to detect if the Ring Alarm system enters the Alarm State (Providing this camera is set to turn the Sirene on when the Alarm State is active)
After that it’s up to you to fill the then column with all bells and whistles you want to turn on in case of an Alarm State 
(I’ve posted a question if there is interrest in connecting the Ring Alarm to Homey, but there’s not much response there, maybe not enough users saw that post: Is there any interrest in connecting Ring Alarm to Homey )
