Texts are sent out with your own message.
Calls are sent out and are (ideally) automatically disconnected. Ending a call automatically may not work with all cell phone providers. Test this feature before relying on it (seriously, no one wants a 3 hour long voicemail).
Here's an explanation of the permissions:
-Read Contacts allows you to select a phone number from your contacts instead of having to manually type it in.
-Send SMS and Call Phone allows the app to send texts and make calls.
-Receive Boot Completed allows the app to re-enable alarms after your phone has been turned off or restarted. Without it, turning the phone off would cancel all scheduled alarms.
-Wake Lock allows the app to temporarily wake the phone to carry out an alarm. Without it, alarms wouldn't go off if your phone isn't being used.