The Security Scheduling option is at the bottom of the Security Section.
Click the checkbox to Activate the Rules Scheduling.
Select the schedule that you think is convenient based on your needs.
TIP: Selecting the column or row titles automatically selects all hours or days.
Please be aware that this scheduling follows the account timezone configuration.
NOTE: If the selected timezone has an offset that includes half an hour, this half hour won't be considered. For example, an account timezone of "India" (+5:30h offset from UTC) will actually have an offset of +5h relative to UTC.