Shruthi firmware flash new built main board

Hey all.
I’ve just built a Shruthi and I’m a complete noob to AVR.
I have a USBasp programmer but don’t know the first thing about how to use the DEV-ENV to flash the bootloader or firmware, any help would be gratefully received.
I have the DEV-ENV running and also have the HEX files compiled. I would only use the ENV to compile HEX files for use in the ST utility for other modules, hence my request.

I’m going to build a Shruthi with boards I bought on eBay. Did you figure out how to flash the blank ic? Can it be done by midi, or do you need a device to to it? I’m a noob too, this is a new avenue for me in diy synth building.

I was new to AVR.
You need an AVR programmer, I’ve got a few but I’ve only used them to update firmware.
I ended up using AVRDude.

Thanks for that information. Now I know what to look for.