How do I like a reply in a course announcement in Announcements Redesign as an instructor?
If you have allowed liking for a course announcement, you can like announcement replies.
If the steps in this lesson do not match what is displayed in your course, learn how to like discussion replies in the classic Announcements interface.
Open Announcements

In Course Navigation, click the Announcements link.
Like Announcement Reply

Locate the reply and click the Like icon.
Like Threaded Announcement Reply
To view threaded replies, click the # of replies link [1].
To like a threaded reply, click the reply's Like icon [2].
View Liked Announcement Reply

The Like icon fills in, indicating you have liked the reply [1].
The Like icon also displays the number of times a reply has been liked [2].