Can't wire my stepper motor to make it work!

Take the black wire and attache it to the arduino ground.
Then attach the white wire to the positive of a power supply giving anything between 5 to 12 Volts.
Attach the negative wire of power supply to the arduino ground.

That diagram does not match up with your photograph, the photograph shows you using pin 1.

it is a bit small

Click on that picture and maybe you will revise that statement.