The breadboard is your sandbox, the easiest way to play around with circuits and try out new components and boards. There’s no need for soldering, you only need to plug wires to connect the rows and build your circuit.
In the main breadboard area (the two chunks with numbers and letters) the pins are connected as a row. Which means, whatever thing you connect in J1 will be connected to what’s connected to F1, too. A1-E1 are a whole different row.
The borders of the breadboard have usually two rails of pins that are connected as a line. They are identified by negative and positive symbols (blue and red lines). This is supposed to be used to distribute power current and GND to the whole board, and most people will use it this way (but it’s not mandatory, just a convention). Notice that the top power rails and the bottom power rails are not connected, but you can connect top and bottom using wires (this is a common practice too).
The drawing below tries to explain how the pins are connected:
Now let’s see a breadboard in action. This is a simple circuit for an LED that is being controlled by port 6 on an Arduino Micro. Try to spot and understand the connections!
This little circuit connects an LED(hole g23) to pin 6 (hole h9 ) of an Arduino Micro, using a 220 ohm resistor. The LED’s negative leg is connected to GND (holes g24 -> j24 -> h14) .
Next: Basic Soldering