To activate alert of lack of components stock for planned maintenance, go through the following steps:   

Step 1:  In the main menu, on the left side, click Settings.   

Step 2: Choose the Maintenance option.    

Step 3: Select the Notifications tab. 

Step 4: In preventive maintenance notifications, select the option: "Components are down for planned maintenance" and define whether you want the alert to be sent the week before or the month before. 

Example of how to activate alert of lack of components stock for planned maintenance: