Where do I find MATERIALS my teacher has put into our Google Classroom?

Log into ClassLink and click the Google Classroom app. Then, click the Classwork link at the top. From this screen, you will see Materials with an icon on the left that looks like page with a ribbon or bookmark in the upper left.

Your teacher may have organized your materials into sections. Scroll and look for that. 

Finally, new teachers to Google Classroom occasionally attach Materials to their Announcements. If you have not been able to find a Material on the ClassWork page, return to Stream and scroll down until you have seen all attachments.