NativeScript is an open source project; as such, it uses technologies that can be freely downloaded from the Internet. You need to download and install a recent version of Node from http://nodejs.org. You also need a text editor so that you can edit your source code. If you are developing for Android, you need to download and install Java 7, Gradle 2.3, and the Android SDK. For iOS, you need to install Xcode 6.2 or a later version.