If you wish to email all students within a certain time period or a course group, you can do so by using the email wizard tool. With this tool you can send emails while applying the following filters: Class, Teacher / Time / Day, Resource / Time / Day, Customer Group, Time Period, Enrollment Type, All Customers, Staff, Product and Location. Principle of using all the filters is the same.
To email all students within a certain time period select Configure > Manage Emails from the left hand navigation, and select All Customers in “All Recipients” field. In a window below click on Add Students to add every registrant from that time period or a course group to a recipient list.
Next step, compose an email and send.