I need to replace my LCD screen. How do I find instructions to replace it?

If it is for a laptop and not desktop as this category is listed under, then you might want to have a service technician replace it. If you really want to go for it, here's some steps for a Toshiba M40:
step one: remove the two screws by the screen hinges, then prise the front panel off, it will simply clip out.

Step Two: remove the two upper screws holding the screen cradle to the back panel.

Step Three: Pull the back panel away from the screen cradle, close the lid most of the way and you should be able to just pull it apart, then remove the cradle screws.

Step Four: remove the screen cable from the back, followed by the lower cable. Done.

6 tiny screws hold the screen in its cradle
2 larger ones hold the cradle to the back plate
2 (Same size) hold the front panel on.

If I'm way off base, then I need to know more info such as the model. If this is for a desktop computer, then you just get a new one and connect it up exactly as the old one is currently connected.