Rule Machine (aka Rule Manager) was an app developed by a community member. Out of frustration with SmartThings about ongoing problems/support he has deleted the app and his license does not allow for further distribution (sorry! you can use it if you have it installed already but not share with anyone)
SmartRules is a paid app that is available iOS from the Apple app store. The version to try out setting up one rule is free. For multiple rules you have to buy the full version ($9.99)
AWAY (all sensors armed), STAY (usually only sensors for exit doors armed, e.g. motion sensors are usually not armed. Often used at night when you are home and want to make sure you are alerted of intruders but don’t want the alarm to turn on when you are walking around the house), and HOME (no sensors armed) are common setting for alarm systems. Usually when you arm the system for AWAY, there is an EXITDELAY (usually 30-60 sec) delay so you have enough time to leave the home and close the door if you arm the system from the keypad. INSTANT is just arming the system without any EXITDELAY. You can set the EXITDELAY in the Digital Life App (this is not a SmartThings setting).
There are many ways of doing this but for your case one option is to set up a routine in SmartThings that turns on the Digital Life System “switch” sets the “dimmer” to 10% if you leave and another routine that turns off the Digital Life System “switch” when you come back. I suggest you also (at least initially) use something like the the “Notify me When” app from the Marketplace to know when the alarm is armed/disarmed.