See the detailed documentation on the Oculus Developer website. In particular, follow the instructions for using Unity with Oculus, and see the recommended specs for Oculus development.
You do not need to install anything extra on your machine to deploy to Gear VR. Follow the instructions at the Samsung Developers’ Website.
Make sure that you can deploy a Unity app to your Galaxy Note 5, S6 Edge+, S6, or S6 Edge (see Getting Started with Android Development):
Plugins/Android/assets
under your project’s Assets
folder (note: This folder name is case-sensitive).Plugins/Android/assets
folder.Steam is required to run OpenVR applications, so install Steam and SteamVR. Once SteamVR is working properly with your headset, add OpenVR to the list of supported SDKs. If you require additional functionality beyond Unity’s built-in support, see the SteamVR asset store package.
See documentation on Oculus Controllers for input control mapping.