question about running ws2812 leds

See if you can follow the code in this example:

//WalkingMarkeeVer2
#include <Adafruit_NeoPixel.h>

#define wait 1000         //viewing time

bool allowWalking = true; //true  >>>---> allows the colors to walk
//                          false >>>---> stationary

#define ledCount 12       //total number of LEDs  <----<<< change to 120, when all LEDs are attached
#define PIN 6             //output pin to the LED strip
#define LEDsPerBoard 6    //number of LEDs on a PCB 

int offset  = 0;          //offset or index into colourArray[]

unsigned long colourArray[] =  //colour code sequence
{
  //example 1:
  //red       green     blue      pink      yellow    white     cyan      orange     black
  //0xFF0000, 0x00FF00, 0x0000FF, 0xFF00FF, 0xFF7F00, 0xFFFFFF, 0x00FFFF, 0xFF3000,  0x000000

  //example 2:
  //red       green     blue      white
  //0xFF0000, 0x00FF00, 0x0000FF, 0xFFFFFF

  //example 3:
  //red     red       green     green     blue      blue      pink      pink      white     white
  //0xFF0000, 0xFF0000, 0x00FF00, 0x00FF00, 0x0000FF, 0x0000FF, 0xFF00FF, 0xFF00FF, 0xFFFFFF, 0xFFFFFF

  //example 4:
  //red       green     blue      pink      yellow    white
  0x3F0000, 0x003F00, 0x00003F, 0x3F003F, 0x3F3F00, 0x3F3F3F    //dimmer

  //example 5:
  //red       green     blue      pink      yellow    white
  //0xFF0000, 0x00FF00, 0x0000FF, 0xFF00FF, 0xFF7F00, 0xFFFFFF  //bright
};

//how many colours do we have
const byte availableColors = sizeof(colourArray) / sizeof(unsigned long);

Adafruit_NeoPixel strip = Adafruit_NeoPixel(ledCount, PIN, NEO_GRB + NEO_KHZ800);

//***********************************************************************************
void setup()
{
  strip.begin();
  strip.show();   // Initialize all pixels to 'off'

}// END of setup()

//***********************************************************************************
void loop()
{
  //cycle through all the colours
  for (byte colourSelect = 0; colourSelect < availableColors; colourSelect++)
  {
    //fill the pixel array memory
    for (byte ledNumber = 0; ledNumber < ledCount; ledNumber++)
    {
      strip.setPixelColor(ledNumber, colourArray[offset]);

      //the next index/offset into colourArray[]
      offset++;
      offset = offset % availableColors;
      
    }// END of for()

    //send the pixel array memory to the LEDs
    strip.show();

    //give some time to view the strip
    delay(wait);

    //*********************
    //move to the next item in colourArray[]
    if (allowWalking == true)
    {
      offset = colourSelect;
    }
    //*********************
    
  }// END of for()
  
}// END of loop()

//***********************************************************************************