To check if the LED strip and power supply work, directly connect your power supply's +12V to the +12V pin of the strip and power supply's ground to each R,G,B pin one at a time to see if they ...

This is a where a Power Mosfet comes in. With the help of the Power Mosfet, we can use the low voltage output from the Arduino ports to control high voltage/current loads -the popular “12V LED strips” ...