Classes are basically buckets to hold media for students to view and interact with. Each class can hold one video and one presentation.
If there is a slot available to add media, you will see a blue plus icon for the class in the class list. Click the plus icon to add media to the class.
Class recordings typically occupy the video slot, and are usually published to their classes as soon as they are finished and processed. If the video icon is light-gray, this is a "placeholder" for the video that will occupy that slot when the class recording is done. These placeholder icons are shown in the above figure along with the green "available" media icons. You cannot add a video to classes with placeholders because you cannot remove a future video that is not there yet. In some cases you can Remove (unshare/unpublish) an existing video from the class if you want to replace it.
For classes that contain or will contain class captures, the presentation slot is free to receive a presentation file to go with the class video. It may be supplemental material to the class lecture or it may be a presentation you show during the class.
If the class has a video (or video placeholder) and no presentation, click the plus icon in the presentation slot to add a presentation to the class. You can select from your content library, or upload from your local computer or shared drive (such as GoogleDrive). You can also create a new presentation to add, consisting of Activity slides or Media slides only. See Adding a Presentation to a Class for more details.
Manually created classes have no media until you add some. If the class has no media in it, click the blue plus icon and select whether you are adding a video or a presentation.
If the class has a presentation and no video (and no placeholder for a scheduled video recording), click the plus icon in the video slot to add a video to the class. You can select from your content library, or upload a video file from your local computer or shared drive (such as GoogleDrive). See Adding a Video to a Class for more details.