Where to get the latest dev build apk

[DeathlyHaven]

I'm actually having some issues with installing the app on my new shield tablet. Just bought the shield k1 tablet and was able to install the version in the store but for some reason it won't allow me to install any of the builds. Anyone have any ideas why this isn't working. Yes I have it set to allow apks from unknown sources I can press install on it I just get "App not installed" message.