What you can do on Classlist varies according to what admin status you have as a member; ie whether you are a parent without admin rights or a Class Admin, Community Rep or Ambassador.
The Ambassador role is automatically given to the initial creator of the site, but can also be assigned to other key parents who play an active role in the school community such as PTA post-holders. Ambassadors can access all areas of the site and can moderate and manage content.
The Class Admin role is usually allocated to someone who can act as the representative for the other parents in his/her child's class/year. If your school operates a system of Class Reps this role is perfect for them. Class Admins can approve parents and view most of the admin features on Classlist in relation to the class/year which they represent. They can also send announcements and create Community events.
Staff Admins have the same administrative powers as Ambassadors in terms of approving and managing parent members, but do not have any access to the parent side of Classlist. This means that they cannot access or moderate any parent-created content (such as posts or listings) and parents can't send individual messages to Staff Admins via Classlist. Staff Admins can still send out announcements and Community events and view parent comments on those.
If you wish do wish for staff to communicate with parents via private messages they need a parent account. We recommend you set up a 'year group' called Staff for them to join. You would give them Community rep status so they can then send admin announcements to any class or group. More info here.
Community Reps can use the admin features to create announcements and community events, but have limited access to the other administrative features. This role is suited for parents with a specific position in the parent community which may not be the same as a PTA position, eg Fair Funding Campaign Officer, Second Hand Uniform Sales, or just someone who is keen to help out from time to time. It can also be used to allow teachers with parent accounts to send announcements to any group.