An update to iOS 8.2 for iPhone coming today to bring support for Apple Watch.
That support is coming in the form of the Apple Watch app. The app will be how you manage everything that you put onto the watch.
Want a new app on your watch? Open the Apple Watch app on your iPhone. There's a specialized App Store for watch apps there.
The Apple Watch app will also be how to configure which friends get priority placement on your wrist, and even which notifications come to your wrist from all of your apps. While we wouldn't mind the ability to manage those from the watch, there's something to be said for the ease of doing it all from your phone instead — it's much better for that sort of organizing of things versus the smaller screen of the watch.