iOS noob: Which directory do I open in xcode to do development in that IDE?

double click on xcworkspace and xcode will load the project

A workspace is a collection of projects. It's useful to organize your projects when there's correlation between them (e.g.: Project A includes a library, that is provided as a project itself as project B. When you build the workspace project B is compiled and linked in project A).

It's common to use a workspace in the popular CocoaPods. When you install your pods, they are placed inside a workspace, that holds your project and the pod libraries.

By andreamazz from https://stackoverflow.com/questions/21631313/xcode-project-vs-xcode-workspace-differences Usually, if it exists, you should always open xcworkspace