You can see if the AutoTutor lesson is in a new tab by looking at the top of your browser window. It might look something like this:
If "AutoTutor Launcher" is the only tab open, then the AutoTutor lesson may have opened in a new window. If this is the case, click the exit button usually located at the top of your browser screen. It's often a red button or an ✖ button.
When the window is closed, your course overview may be behind it.