The breadboard has many holes arranged in columns and rows.

The top rows and bottom rows are used as positive and negative rails. That is, you connect the positive and negative of the battery here.

The columns are used to connect the components. .

When you push the wires into the breadboard they make an electrical connection with the conductors inside the breadboard.

The shaded areas show how the rows and columns of holes are connected inside the breadboard.

All connections are horizontal.

The smaller breadboards are connected in a slightly different way