Macbook + Arduino Nano + WS2812b not working

Hi
This is my first Arduino project but I'm not getting anywhere.
Can someone help me find the problem?

I have a Arduino Nano on a mini 170 breadboard connected to the USB port of my Macbook
There's a external power supply 5V 10A connected to the end of my 5m WS2812b 60 LED/m (300 LEDs)
Data connected to data pin 6 and GND connecting the LED strip to the Arduino

I'm just trying to test my LED strip so I can go on with my project but I cannot get it to work
When connected to the power supply, the first LED lights up in green and there's no change connecting to the Arduino.

I've tried different codes (CollorPallet from FastLED, Neopixel Adafruit etc) and nothing changes.
I've tried different data pins.
I've soldered different cables to check if they where broken.
I've tried to manually connect the data pin to the other LEDs to check if the first one is corrupted.
Nothing seens to work.
I took some pictures and there's a schematic on how my circuit is done. ATTENTION: the schematic is only one example, I AM using a 5V 10A external power supply

#include "FastLED.h"

// How many LEDs in your strip?
#define NUM_LEDS 300

// For led chips like Neopixels, which have a data line, ground, and power, you just
// need to define DATA_PIN.  For led chipsets that are SPI based (four wires - data, clock,
// ground, and power), like the LPD8806 define both DATA_PIN and CLOCK_PIN
#define DATA_PIN 6
//#define CLOCK_PIN 13

// Define the array of leds
CRGB leds[NUM_LEDS];

void setup() { 
     // Uncomment/edit one of the following lines for your leds arrangement.
     // FastLED.addLeds<TM1803, DATA_PIN, RGB>(leds, NUM_LEDS);
     // FastLED.addLeds<TM1804, DATA_PIN, RGB>(leds, NUM_LEDS);
     // FastLED.addLeds<TM1809, DATA_PIN, RGB>(leds, NUM_LEDS);
     // FastLED.addLeds<WS2811, DATA_PIN, RGB>(leds, NUM_LEDS);
     // FastLED.addLeds<WS2812, DATA_PIN, RGB>(leds, NUM_LEDS);
     FastLED.addLeds<WS2812B, DATA_PIN, RGB>(leds, NUM_LEDS);
     // FastLED.addLeds<NEOPIXEL, DATA_PIN>(leds, NUM_LEDS);
     // FastLED.addLeds<APA104, DATA_PIN, RGB>(leds, NUM_LEDS);
     // FastLED.addLeds<UCS1903, DATA_PIN, RGB>(leds, NUM_LEDS);
     // FastLED.addLeds<UCS1903B, DATA_PIN, RGB>(leds, NUM_LEDS);
     // FastLED.addLeds<GW6205, DATA_PIN, RGB>(leds, NUM_LEDS);
     // FastLED.addLeds<GW6205_400, DATA_PIN, RGB>(leds, NUM_LEDS);
     
     // FastLED.addLeds<WS2801, RGB>(leds, NUM_LEDS);
     // FastLED.addLeds<SM16716, RGB>(leds, NUM_LEDS);
     // FastLED.addLeds<LPD8806, RGB>(leds, NUM_LEDS);
     // FastLED.addLeds<P9813, RGB>(leds, NUM_LEDS);
     // FastLED.addLeds<APA102, RGB>(leds, NUM_LEDS);
     // FastLED.addLeds<DOTSTAR, RGB>(leds, NUM_LEDS);

     // FastLED.addLeds<WS2801, DATA_PIN, CLOCK_PIN, RGB>(leds, NUM_LEDS);
     // FastLED.addLeds<SM16716, DATA_PIN, CLOCK_PIN, RGB>(leds, NUM_LEDS);
     // FastLED.addLeds<LPD8806, DATA_PIN, CLOCK_PIN, RGB>(leds, NUM_LEDS);
     // FastLED.addLeds<P9813, DATA_PIN, CLOCK_PIN, RGB>(leds, NUM_LEDS);
     // FastLED.addLeds<APA102, DATA_PIN, CLOCK_PIN, RGB>(leds, NUM_LEDS);
     // FastLED.addLeds<DOTSTAR, DATA_PIN, CLOCK_PIN, RGB>(leds, NUM_LEDS);
}

void loop() { 
 // Turn the LED on, then pause
 leds[0] = CRGB::Red;
 FastLED.show();
 delay(500);
 // Now turn the LED off, then pause
 leds[0] = CRGB::Black;
 FastLED.show();
 delay(500);
}

Thanks for the help!

have you tried the exaples first.
maybe the arduino is not connected right.