Rocz3D has done a pretty comprehensive series on Blender Modelling on Vimeo. You can access them on the Vimeo site or via Rocz3D’s channel here.
Zombies, Run! now allows you to put add-ons onto your buildings to further increase your stats (although I’ve yet to see my stats increase from said add-ons). If your app crashes and locks you out of your base screen, there’s an update just released to the Android app — update it and try again.