I have a large USB drive connected to the rear USB port, but it will need to be a FAT32 formatted drive as the player does not support NTFS. To play back video files, you go to the Home Menu (there's a screen shot of this menu in my review), select Movie, and then pick the USB device you want to look at. At that point, you see a file manager sort of interface with a list of all the folders on the USB drive. You can navigate that folder structure and the player will list all of the video files that it supports. There are some page up/down buttons that let you jump up and down one screen at a time (about six or eight files/folders per page). It's not really the most robust interface for a media server, but it is serviceable and I use it for some of our daughter's videos.