Where do I see past messages sent by teachers?
There could be two places.
The quickest place to check is your dashboard. When you first login, you are viewing your profile. Near the top of the page is a link to your dashboard, which displays recent messages, upcoming events, and more
The other place is on the teacher's homeroom page. Go to Classrooms, then click on the classroom for the teacher whom sent the messages. Scroll down to see the list of recent messages.