hey there ,
i have a question, can u turn on and off any LED on the led strip( SMD2812 ) u want and how do u programm that. i need something for my project at school and i need to know how the programm Works and stuff
Those strips work with the Adafruit Neopixel libraries. These libraries include a lot of useful example code to get you started.
You can install the library using the IDE's Tools/Manage Libraries menu function, or you can download it here.
Adafruit's documentation is also pretty good.