Sorry if the title is a little confusing. I couldn't think of a better way to word it. Also sorry for the bad soldering job. It's the first time I've tried to do anything like this.
Nano: Nano clone from amazon, UCEC USB Development Board ATmega328P CH340G 5V
If you have a multimeter, then you can check the led with a diode tester. In most cases the current from the diode tester will also light up the led some.
You have to check a number of things. Can you display text to the serial monitor, is the RGB led doing something and so on. But more important is that you make a few small test-sketches and test everything one by one.
It is a beginners mistake trying to make the final project work. If that does not work then someone want us to tweak one small little thing to make it work. However, we are no magicians, so all we can do is trying to help to test everything one by one.
There was another thread about this a few days ago but the protagonist only had two or three of those displays working. Any attempt to add more was recognized as needing a change to how power was supplied.
It looks like you're running power from the Nano. I doubt that it can manage to run that many displays.