Relay issues

The goal of this project is to control 12vDC solenoid valve. I bought this and am having some trouble getting everything to work. My first hack at it was to hook power/ground/in all up to the arduino board. I am able to turn on the light sensor but am not able to flip the relay. My second method was to hook power/ground up to a 12vdc transformer and in to the arduino board which wasn't even allowing the In indicator to light up. I feel complete lost and have searched and searched for the right solution. If anyone has some helpful input I would really appreciate it. Thanks.

If you buy from Sparkfun or Adafruit, you get good and useful items and with the information how to use it.

The relays are 12V. So you need 12V somewhere. You have to follow the traces on the pcb how to use it (reverse engineering).

Connect Vcc to your 12V +ve line and the GND of the 12V -ve line, also connect this point to the arduino ground. Then the IN connections go to the arduino output pins.

thanks. Ok, so I did have it set up before but wasn't able to get anything working. Its a small solenoid so power shouldn't be an issue. I'm just running a straight line in to the relay to power the external object correct?

Can you here the relay click when you switch it with the arduino?