To repair a camera LCD screen, you need first to find the right replacement LCD screen, remove the screen, replace the screen, test the LCD before fitting it in, and reassemble it. Other parts inside the camera might be faulty causing the display not to work, and only a trained professional can quickly diagnose and fix it.
Find a replacement screen that fits and works with your camera. Track the right screen using the camera's model number, and if you can't find one, buy a faulty camera that is the same model with the screen intact.
Carefully remove all the screws and housing without touching the circuitry. Remove the battery and memory card before dismantling, and place all screws in a safe place so you don't lose them.
Many digital cameras have their LCD screens plugged into the circuitry board, and detaching the screen should be as easy as pulling out the plug. Other cameras might have their screens soldered or glued to the boards. Use a soldering iron to detach the screen.
Fit the new replacement LCD into the board by soldering or plugging it in. Avoid touching the screen during the reattachment.
Insert the battery back, and test the new screen works before fitting it in, so you do not have to disassemble it again if the display doesn't work.
Fasten the screws to the camera's housing; once you're done, make sure the camera works, because tightening the case might loosen some connections.