In the main navigation, click on "Manage files".
Then click on "Add > Upload" and select images, audio files and videos from your computer. Files you have already uploaded can later be reused in different stories.
You can also just drag audios, images and videos at once and drop them into the editor
Before uploading, you can edit the metadata of your files. Click on a file in the list on the left side and enter rights information in the right column. You can also specify how the rights information of the files should be displayed in the story.
Finally, click "Start upload".