How do I change the light bulb

@smgmac of course, you already know there are no light bulbs. your TV uses LED strips to light the screen. Since there are multiple reasons that could be the cause for a black screen, you will have to make sure that this is a backlight issue. First we need to know if you have sound at all or if the only sign of life your TV has is the power LED that lights up.

Dim the room and turn the TV on. While you do that, use a flashlight and shine the light beam at an angle against the screen. See if you can make out shadows or shapes. If you do, then it is your backlight that has failed.

If you do not see anything, unplug your set and remove the back cover. Then visually check the boards for any obvious damaged components. Check all the wiring and unplug the wires and plug them back in, make sure they are properly seated. Post some images of all of your boards with your question. Use this guide Adding images to an existing question for that so we can see what you see. It is possible that this is either a power board or a T-con board issue.