To get into google classroom one must first login to his/her school google account. It looks just like gmail although there is no mail capability.

Username:

Click on the nine squares in the upper right corner and choose the classroom app.

You are in! You might be asked to join the class....join it! 

Note: If the classroom app does not appear in the pull down menu you may also access it by typing classroom.google.com in your search bar.

You can also access your google doc by clicking on the doc or the drive apps.