You could put those MOSFETs and 2-pin connectors on a protoshield and plug the shield onto an Uno. Or use a seperate standalone board.
The gates get driven by IO pin thru 150 ohm resistor, one leg goes to common ground, the other leg goes a screw terminal for LED-, the other screw terminal gets 12V for the LED+.
Connect +12 & Gnd to your source. Connect the 12V source ground to the Arduino ground.
Can drive 6 MOSFETs from 6 PWM pins.
Need more PWMs? Can do software PWM as well.