Tutorial 1: Environment Setup
Go to Apple's developer center and register a free account. This will allow you to download latest iOS SDK (while you are still beginner please don't use any iOS betas). Once iOS SDK downloaded open the DMG image and install SDK into "/Developer" folder. It is important to install exactly to that folder as NimbleKit while install process will look for iOS installation exactly at that location.
After iOS SDK is installed it is time to download and install NimbleKit. Go to NimbleKit's home page and download latest version. As iOS SDK is the only software required to be installed on the computer in order to use NimbleKit (iOS 4.2 or newer required) we can install NimbleKit now.