What do you do when your Nikon camera shoots dark?

What do you do when your Nikon camera shoots dark?

Take the lens cap off.

Learn to use it properly, starting with the manual.

Not a whole lot of information here to work with. Perhaps you could elaborate a bit?

Read the manual.

You need more light. It's over exposed. Then is it underexposed? Still learning.

You could try increasing the ISO or decreasing the shutter speed