When you click on your teacher, it will take you to Teams. You'll be in the "Posts" tab. You can send messages to your teacher and class in the Posts tab. To find your lessons, click on the Class Notebook tab at the top. Then click on the arrow on the left (it looks like a 'greater than' sign). You'll see your name and all the school subjects.
Check out this video for a guide to using Teams and finding your assignments.