There should be a frontend icon. You can also set a code. (I’m doing this, and coupled with HADashboard it’ll hopely function as a great alarm system.) There’s someone on the forum who expanded the manual alarm component so you could see which monitored sensors are open an the moment of engaging the alarm, and some other features. I hope he’ll file a pull-request soon.
edit: here is the thread: A different take on an alarm system