Connect your MOD unit via USB, upload your gen_exported.cpp and gen_exported.h files and give the plugin a name.
When all is ready, press the "Build" button and wait for it to complete, then press the "Install" button to push the plugin build into your unit.
Make sure your unit runs release 1.13.3 or later, which is needed for receiving builds from this service.
Chrome and other Chromium-based browsers only allow the USB connection from the https version of this site, and ask for permission to access your local network the first time; Firefox and Safari only allow it from the http version. You are sent to the right one automatically, or pointed to it if the connection fails.