Since every human has a different DNA (different combinations of C, G, A, T) what does it mean to have the genome done? I'm confused about the difference between genome and DNA. Is it correct to say that the same type of bacteria has the same DNA? But my understanding is that it is not correct to say that the same type of human has the same DNA, since every human has a different DNA. What am I missing here?
All humans have some differences in their DNA, but there's far more that is shared. On average the difference between humans is only about one thousandth of their full DNA, which means we're about 99.9% the same. These differences aren't distributed fully randomly, but are often because of specific gene alternatives. (Random mutations do occur, but they are also often fatal, so the random mutations we see of living adults are much more restrictive than all the random mutations that occur.)

To identify the human genome is to study many people's DNA and to label the parts that are shared between everyone, the parts with two or three variations, and the parts with even more variations. Even though every person has different DNA, we can still say they fit the pattern, just like every T-shirt may be unique but they all fit the T-shirt pattern and not the trousers pattern.