Long story short, I was unable to find much, if any doc on these things...
But, I still managed to get the board going with the LCD. The rest is easy as it is standard ESP32C3...
To use the board, you need to download the Espressif board managers in Arduino IDE.
The board to select is "ESP32C3 dev module"
These schematics are however, not 100% correct. Among other things, they lack the LED on IO8...