There are several ways to do this.  See links below on more detailed info.

1. Manage Images and Files area
   1. Standard Uploader
   2. Java Uploader
2. FTP
3. YouTube Embedd Code video
   
4. YouTube instructions

Here is a list of file extensions that are supported when you have the "new Video player" enabled on your site:

the following video file types are converted into the "mp4" video format:
'asf', 'asx', 'wmv', 'wm', 'wvx', 'wmx', 'mov', 'qt', 'm4v', 'm4p', 'mpeg', 'mpe', 'mpg', 'm1v', 'm2v', 'flv', 'f4v', 'f4p', 'avi', '3gpp', '3gp', '3gp2', '3g2', 'rv', 'rm', 'ivf', 'vob', 'divx', 'xvid', '264', 'h264', 'mp4v', 'mkv'.

And the following audio file types are converted into the "mp3" audio format:
'f4a', 'f4b', 'm4a', 'm4b', 'm4p', 'mp2', 'mpa', 'm3u', 'ogg', 'flac', 'ape', 'ra', 'ram', 'aif', 'aiff', 'aifc', 'au', 'snd', 'wav', 'wma', 'wax', 'mid', 'midi', 'rmi', 'mka', 'aac', 'adts', 'dts', 'wv', 'wvc'.

To enable the "new video player" on your site please contact support and ask them to enable it for your site.

NOTE: Our server has limit setting set to 51 MB at a time(files larger than that will not upload with the regular uploader).  However the Java Uplaoder splits files to small pieces when uploading to the server, then puts them back together.  please use the Java uplaoder or FTP for large files