This is page 2 of 4. "Practicing" begins here.
Against a dark background the problem is the opposite.
Your subject will become over exposed. The camera program concentrated on the background. It severely over exposed the little Snowy Egret. Also, the shutter speed was so slow that the background, while properly exposed, ended up blurred.
There’s no salvaging this picture.
In the picture below; the camera’s program used settings for the dark background which caused the Heron to be over exposed. But in the amount of light it reflects, the Heron is a lot closer to the background, than the Egret above. So even though the camera exposed for the background, it captured a salvageable picture.
I sent it through one of my editing programs and that brought it up to par.
Now it looks Pretty good.