Open the settings tab within ScreenTrust Management System and navigate to the "School" tab.
The following settings are used to determine when the ScreenTrust Teacher app can be used, and when a device is considered to be "at school" 

Home Schooling:

If homeschooling is supported, a student is not only considered 'at school' if it is connected to the school's network, but also if the current day and time is within the configured school hours.

School Hours:

School Hours determine when the Teacher app can be used, when activity should be logged and to apply certain policies.

School Network:

Configure the public IP addresses of the school network the students connect on