Share LAN and WAN for PCs. Mobile devices you'll need a (L) series router. DIR-885L or DIR-880L for starters...
The 882 is DLNA supporting so your PC and Mobile devices have to have DLNA support as well. If you have video files, like MP4s stored on the USB drive and you have the media feature enabled on the router and the router detects the drive, then the drive is automatically shared and detected by DLNA enabled devices and should play supported media files from the USB drive. This would be the only sharing support this model router supports...