You get to the Alarm Setup Window by clicking the Alarm Setup button in the Logger Setup screen. Most loggers allow you to set high and/or low alarm thresholds for each logger channel, or disable these alarms. Alarms are set by entering the thresholds as shown in the window below.
The checkbox to the left of the low/high alarms enables the alarm when checked, and disables the alarm when clear.
Alarm resolution and availability is logger dependent. Check the logger documentation for more details.