It's simple. Just look for the rubber pads and take the screws out.
The screen surround should unclip in several places depending on your model around the screen. If it feels as though it's going to snap, stop. Just double check if there are any possible places a screw could be lying around the area.
Some are stiff, I know the advent models are particularly tough with double sided sticky tape (ECS rebrands).
Once that's off, it's usually obvious what to do from then on. Just make sure the harness cable and inverter cable are of the same type as the screen you are replacing it with, and that obviously they are the same resolution screens.
Going in to a bit too much detail there though I think, it really is simple in most cases apart from maybe the newer Sony's.