Just like a regular DVD player, put the DVD into the console like a regular disc, then it should play.
If it doesn't, then go to "Browser" menu, then you should be able to see a disc on the screen. Click it and it'll play.
The only reasons why it might not work is if the console is:
1) region locked
2) the lens is dirty or malfunctioning
3) The disc is scratched or dirty
4) the console is broken
But yeah, just do that.