This Mini Breadboard (Clear) is a half-size solderless breadboard with 400 tie points. It has a standard double-strip in the middle and two power rails on both sides.
You can just put these solderless breadboards together either way to make a longer and/or wider breadboard.
The top and bottom rows (the rows indicated by the blue) and are usually the (+) and (-) power supply holes and these move horizontally across the breadboard, while the holes for the components move vertically Each hole is connected to the many metal strips that are running underneath. Each wire forms a node.