Initial Operation

[Weaver]

Hello,
I've never had any luck in getting video players going in the Linux environment, mostly because I haven't had the time to devote to the situation. So, I've decided to rectify that. At the moment, with Debian Sid, I have SMplayer installed with MPlayer providing the backend.
A 10 year old could probably handle it, but I wouldn't know a demuxer from a wooden spoon. I can get the first track on a dvd, but only audio, which keeps recycling. No video.
I've been here: and installed just about everything with the appropriate line in /etc/apt/sources.list, but the situation described above is the best I can get.

Is this a common situation?
Any clue as to where I should go from here?
What can I provide to assist with analysis?
Thanks for any time and trouble.

Weaver.