How do I Change a 2000 Jetta Brake Fluid?

My Brake Light keeps blinking on an off, when I'm driving.

I believe I need to change my brake fluid. I opened the hood to change it and took the top off but its kinda full. The Fluid in there is also very black.

What should I do from here? should I use something to take the old fluid out then refill it?How do I Change a 2000 Jetta Brake Fluid?it will take 2 people to drain the brake fluid. you need to raise the rear of the car up, have someone pump the brake pedal a couple of times then hold it down while the other person opens the bleeder valve. after the fluid squirts out, continue to hold down on the brake pedal until the valve is closed. repeat this process on both the rear bleeder valves 8-10 times each. make sure that you keep an eye on the fluid level in the master cylinder. do not let it go empty. after the fluid is almost gone from the master cylinder, fill it back up to the full mark and repeat the process again. this should get almost all of the old fluid out of the brake lines. fill again and you should be ready. make sure the float in the master cylinder moves freely up and down.