Grbl Image File Download
You should see a message like this 'Grbl x xj ['$' for help]' if you dont see the message, make sure that your are connected to the correct port and use the baudrate of 115200.. Now with firmware on your board you need to adapt grbl to your specific machine To communicate with your board you need to open the arduino ide serial monitor. https://rymptesmoma.mystrikingly.com/blog/download-3gp-converter-for-for-windows-10
ae05505a44 HERE