Those with Teacher or Staff privileges in Aeries Communications have access to direct message any other staff member. 

Teachers have access to direct message class members and guardians and can send class announcements. (Note: Students are members of classes, not parents, but our system will cc parents on any announcement unless filtered otherwise. See: Announcement Subsets).

Staff or Teachers who are Group Owners have access to direct message Group members and can send announcements to the Group as well.

This video takes a quick tour around Communications - you will find that creating an announcement has been enhanced since this video was created, but the rest of the overview is spot-on if you need a quick review:

Training Playlist - Teachers & Staff

Aeries Teacher Walkthrough Printable PDF

Teachers and Staff Members will access Communications through single sign-on through the Aeries Portal:

As of 7/29/2019, any new member who receives their first SMS/Text notification from a district, school, class or group (or current member who re-enables SMS notification preferences) will also receive automated instructions on how to opt-out (STOP), display the instructions again (HELP), and opt back in for SMS/Text notifications (START). This process follows industry standards.