A breadboard provides an easy way to create electronic circuits. It is a plastic board with lines of holes for holding either electronic components or connecting wires (jumper wires). The lines of holes are connected as shown by the red arrows in the diagram below. The pair of lines down the side of the board marked with blue and red in the diagram are for the power connections. They are known as the power bus. Usually, the best approach is to connect one side of the breadboard to the power supply, and to connect the power bus on the opposite side with jumper wires as shown. In the bottom image, power is being supplied by an Arduino prototyping board, but could also be supplied by a battery. When several power sources are used in the same system, all of the ground (negative) pins should be connected together to form a common ground. This ensures the correct voltage difference across all components in the system.
The other lines of holes are connected across the board in groups of five. You use these to connect components together by inserting their pins in appropriate places. You can also use jumper wires to make connections from one row to another, or from the breadboard to a pin on an Arduino prototyping board, for example.