1. Click on the New Post button:
 

2. Next to Post Type, select Question:

3. Next to Post to, select the audience for your post. You can post to the entire class, a class group, or individual students and instructors:

4. Select the folder(s) to post in:

5. Fill out the contents of your post:

6. (Optional) Next to Posting Options, select if you want to send an email notification about your note immediately, bypassing students' email preferences; or add this post to your students' reading lists.
 

Finally, click Post My Question!