To annotate an audio or video file, you must be logged in with Author privileges for the Scalar book containing the media. Navigate to the media in Scalar, and click the "Edit annotations" button at the bottom of the page. This will launch the annotation editor. Once in the editor:

1. Click the plus button on the left to create a new annotation. The new annotation will be created at the playhead's current position in the file.
2. Enter the title of the annotation.
3. Use the two "Set" buttons to set the in and out points of the annotation to the current position of the playhead.
4. Enter the content of the annotation (optional).
5. Enter an abstract for the annotation (optional). Whatever is entered here will be displayed alongside the media instead of the content above, which will be "saved" for when the reader navigates to the annotation's dedicated page.
6. Click "Save" to save the annotation.

Additionally, you can click any annotation in the annotation list on the left to select it. Selected annotations can be edited using the provided form, or deleted by clicking the minus button. When you're done editing annotations for the file, click "Done" to return to the page for the media file.