Go to start my car and all the lights in the interior flicker on and off?

Please don't disconnect the battery while the car is running, it is bad for the computer system. It does sound like the battery is bad though, but to be sure turn the headlights on for 10 minutes and then turn the engine over if everything goes out the battery is no good or you have a bad connection to the battery. These guides should help fix it:

https://www.2carpros.com/articles/car-battery-load-test

and

https://www.2carpros.com/articles/everything-goes-dead-when-engine-is-cranked

To replace the battery this guide can help walk you through and I have included instructions for your car in the images below.

https://www.2carpros.com/articles/how-to-replace-a-car-battery

Check out the images (below). Please let us know if you need anything else to get the problem fixed.