Breadboards are used to prototype circuits very quickly. It looks like a block of plastic with a bunch of little holes in it. To use it, you just push your parts straight in to the holes. But, to connect your parts, you can't push two parts into the same hole at once, so how do you connect all your parts together? To solve that problem, breadboards have a neat little feature in them. If you look at a breadboard so that the bars on either side are horizontal, the holes in each column are all connected together (NOT horizontally!). If you look at it the other way, all the holes in the rows are connected together. The holes can never disconnect. The break in the center is there so that ICs (integrated circuits, aka chips) can be pushed into the breadboard. If the break in the center wasn't there, then the pins on your chips would all short together, and your chip might blow up.
Now, to those bars on either side. Those are used to distribute power throughout your breadboard. The holes in these bars all connect side to side (if you look at it so that the bars are horizontal). If you look at it the other way (the bars are up and down) the holes in the bars are connected up and down. Some types of breadboards will have a break in the middle of the bars, so you will have to connect the two sides with wires. To power your breadboard, you put the positive side of, say, a battery to the red side (if the breadboard is colored) and the negative side to the blue side. They don't have to be that way, you could have the wires flipped around, but for the sake of simplicity, I recommend you plug your power source in the way I showed.
And, if you're wondering why it's called a breadboard, read on. Before modern breadboards were available, people would prototype their circuits on planks of wood, sometimes even actual breadboards. So, the name for anything you prototyped a circuit on eventually was just called a breadboard.
Intel 8808 computer built on a breadboard