The Discussion tool allows students and instructors to post and respond to conversations on specific topics.
When you click on the Discussion button on the left hand side under Content, you will have a view that looks like the one below:
Here you can see the Discussion Forum topics. To access and add a comment to the discussion, click on the topic.
In the image below, you can see that there are 3 unread posts. To read these, click on the number 3 and the unread posts will open.
You can choose how to display message on your screen by changing the setting to either List View or Thread View. This option is found in the top right hand corner of the Discussion Forum as shown below: