How to push code to ATMega328P using Arduino Micro and ICSP

Hey there people,

I am new to the world of Arduino and not at all an expert in electronics but trying to work through it. So I have a project a friend helped me build the circuitry for. Essentially, this project is a small board with SD card that plays some tones with the pressing of different buttons.

The script is pretty straight forward, when button 1-4 is pressed, this triggers a stored WAV file on the SD to be activated. I have updated the script and need to now push the script to the board using my Arduino Micro but don't know the best way to go about doing this. I know there is a way to do it by ISCP connections.

All the help is greatly appreciated. by the way the receiving board is a 3.3V


It's complicated and tricky and I have tried several times and not got it to work. Why can't you connect your device directly to your computer and download the sketch from there ?

Because the project board is a stand alone circuit (no micro USB connectivity) hence the need to use the ICSP jumpers from the Arduino Micro. I just don't want to fry the project board so any help is appreciated.