Let me just restate the question to make sure i understand correctly, you have movies on your dns -320 and you want to play them on your LG T.V.? If that is correct then the first question is your T.V. have DLNA capabiltities? If it is a newer T.V. then it probably does either thru wireless or by ethernet in the back of the T.V., I would suggest to check the manual if unsure.The next thing you would need to do is to enable UPNP server in Applications settings in the DNS-320 so that your T.V. will be able to pickup the server.Once enabled you can leave it to scan the whole DNS 320 for media files or you can select just a specific folder and the NAS should be ready to display movies once it scans for them.
The next tricky question is will the formats you have be able to be seen by the DNS-320? look in your manual to see the types of formats the DNS 320 displays, or just look around in the forum i am sure you will find a thread that has it.If your formats are not visable by the NAs then when you go to play the movie it will not play.