Overview of the Alarm fields
Enabled
Enabled or not. You might want to keep a couple of alarms around that are disabled, just so you can "start polling now" towards the end of the movie/game/day/night.
When to schedule alarms
Time
The time of day to run repeated alarms or a single alarm later in the same day.
Repeat
What days of the week to repeat.
What to look for
Line
Which line/route.
Station
Which station/stop.
Destination
The headsign/destination.
Max Time
The maximum predicted arrival time that would still be considered a match. Set this higher if you don't mind waiting a bit more. Note: If you really don't mind waiting, JUST GO!
Min Time
The minimum predicted arrival time that would still be considered a match. Say it takes you 5 minutes to walk to the stop, you might want to set the minimum to 6-7 to give you some padding. More, if you need more prep time.
How to let you know
Ringtone
The ringtone to use.
Vibrate
Whether to vibrate or not.
Label
A label to make the alarm a bit more meaningful to you, for example: "go home!", "from Dan's", "to the gym"