i bought a LED power supply 12V 12.5Amps,
WS2812 strips require a 5V supply. 12V will damage them.
Show us a good schematic of your circuit. Show us a good image of your wiring.
i also noticed something that may help with finding the mistake, when i turn on my setup its not working right?
You are waving your hands in the air and running in circles.12v has probably damaged your LED strip and maybe even your Arduino.When asked to provide useful information, you refuse, but show some else's work.Why should we spend any more of the 'our' time to help you?