Step 1: The first step is to open CommonLit | Free Reading Passages and Literacy ... and click Library
Step 2: Click Featured Content
Step 3: Click desired article
Step 4: Click ASSIGN TEXT
Step 5: Click desired class
Step 6: Click Date:
Step 7: Click desired date
Step 8: Click ASSIGN
Step 9: Click ×Close
Step 10: Click My Dashboard
Step 11: Click Assignments
Step 12: Click chosen class
Step 13: Click three dots menu
Step 14: Click Share Assignment
Step 15: Click choice for Google Classroom
Step 16: Click SHARE
Step 17: Open Google Classroom and navigate to class. Click assignment from Commonlit.org
Step 18: That's it. You're done.
Here's an interactive tutorial for the visual learners
https://www.iorad.com/player/140124/Commonlit-org-to-Google-Classroom-Assignment-Sharing