this should work with your aspen watch let me know if it doesn't
For the alarm
: If you want to use it (I think both it and the light use battery faster than when not used), you set it by pushing mode button twice, as indicated above, then go to hour or minute setting by pushing the lap/reset button, and advance to the time you want by pressing the start/stop button. Pushing mode will take you back to normal time again.
To turn alarm on or off, hold lap/reset button in and at the same time push the start/stop button. Alarm icon will show on or off. When you release the lap/reset button, it will revert to normal time.
If the alarm is on, at the designated time it will start beeping for awhile or until the lap/reset button is pushed (off) or start/stop button (snooze).