I’m not sure I can help much as I use Visual Studio with Voltbuilder.
Basically, I created the necessary folders (certificates, www etc) and added the files and then manually created the voltbuilder.json, I zip it and upload it via the web UI. I know some of the other (more experienced) developers use nodejs to push their builds to volt.build.
From their I use the Over The Air (OTA) to download and install to the device.
Start building native app with Volt.Builder - make sure all cert’s and signing files are copied to the “certificates” folder (will be generated automatically).