At this time dotCal supports 1 alarm per event. If you have entered more then 1 alarm from a dotCal connected calendar client, all the connected clients will continue to support the multiple alarms but dotCal alarming will only support the first one entered.
We have added this to our requested feature list.
Alarms for an event are set from within an event bubble. Click on an event to open the bubble. They can be added or edited later.
The default for an event alarm is none. We plan on adding many different kinds of alarms in the future. Click the alarms pull down box to see what is enabled.
Alarms set from within dotCal may also show up in your calendar client and is dependent upon your client calendar settings.