This is the code and pictures that I use for my 64x64 LED Matrix display.
The blog post on how to make it can be found here: https://www.djanes.xyz/how-to-make-a-portable-led-backpack-sign/
The code that drives the display is from https://github.com/hzeller/rpi-rgb-led-matrix
Check the blog post out for a 2200+ word tutorial.