How do I leave lesson notes for an entire session roster?

This article explains how to provide lesson notes for the entire session roster

To leave notes for all the clients of a session, navigate to the session for which you wish to message all clients. Then, click Message Session Clients. 

Next, specify a date range. All clients within the specified date range will be recipients of your message. Then, provide a message.

You can also attach files to be included with your message.

When you are finished, click Message Clients to send a message to all clients of the session for the date range specified.