When the video you uploaded on the server is ready for use, it appears on the list in the media library. You can see a thumbnail image of the video as well as its duration, and you can also preview the video.
As the video is uploaded on the server, it is automatically converted to the right format. This may take a while. If the video you uploaded is not displayed properly, the upload and conversion may not have been finished. Wait a minute and if it still doesn't appear right, refresh the view by pressing F5 on your keyboard or by pressing the refresh button on your browser.