Just in-case anyone else is having this issue: Assuming you have the GardenApp (Part1 Start) open in Xcode, on the left hand code Navigator, select the "GardenApp" file (which has most of the app code files as children) and you'll see on the right hand side, a file that looks like a bunch of project settings and configurations. You'll see two main headings on the left, "Project" and "Targets". Under targets is "Garden App", select that. Scroll down to "Signing" and you'll see "Development Team", select the your team (that you setup in "Xcode" -> "Preferences" -> "Accounts" -> "+".). After this you should be able to preview and build the Garden App. Why this isn't specified somewhere more obviously in the documentation, I'll never know. Hopefully this description is good enough to resolve yours and other peoples difficulties.