Background
Chatting is a guided text conversation the teacher can monitor, join and direct, aimed to test and/or evaluate the students' writing skills.
As opposed to Show chat window 
in the Class view, you can save this chat session.
Procedure
Proceed as follows to create a Chatting activity:
- Under Activities, select Chatting.
- Fill in the subject for the chat session in the text field.
You can also add an attachment and set a timer.
- Click Start activity once all students are ready.
Result: the Chat activity dialog box opens on the students' screens.
- Join the conversation as a teacher by typing in the text field at the bottom of your screen in the TCC
- Click Stop activity
when the activity is over.
Warning: Do not forget to save the conversation 
if you want to hold on to the chat session.