After accessing the DFU state in your PCB, build the default layout using:
make viendi8l:default
Then download the resulting binary `*bin` file using `dfu-util` or QMK Toolbox.
See the [build environment setup](https://docs.qmk.fm/#/getting_started_build_tools) and the [make instructions](https://docs.qmk.fm/#/getting_started_make_guide) for more information. Brand new to QMK? Start with our [Complete Newbs Guide](https://docs.qmk.fm/#/newbs).