If you are working with small video files (<30MB) that have an .swf extension, the best way to use them is to embed them within a web page inside Desire2Learn. However you create the web page (a new news item, a quiz question or answer, or a new content topic - new file), use the Insert Stuff button on the advanced formatting toolbar to embed the video. In addition to providing the correct embed code automatically so that the video plays without any scripting errors, this also allows you to type instructional context for students to read before they watch the video.
I am the distance education coordinator at Cosumnes River College in Sacramento. I also teach a class on how to be a successful online student and the occasional classes in history and how to be a healthcare IT trainer.