You can enable several features by clicking on the red areas of this window and once it turns green, it means it's enabled and working. In this section we got:
Alarms for when another player is attacking you;
Alarms for when a player is seen in your screen;
Alarms for when creatures are seen in your screen;
Alarms for when your health or mana is below a certain %, which is configurable by sliding the bar located to the right of it;