15 STEPS
1. Open your google doc and highlight the text you want to comment on.
2. With your mouse, click and drag highlight, then drop it on highlight
2b. Drop
3. Click comment
4. Type your comment or add others with @. With it typed, click "comment".
5. To edit a comment once posted, Click More options...
6. Click Edit
7. Type Comment draft. Edit your comment...
8. Click Save changes
9. To reply to your own comment or the comment of others, click Reply. Reply or add others with @
10. Click Reply to comment
11. To delete a comment, Click More options...
12. Click Delete
13. Click Delete
14. Click highlight
15. That's it. You're done.