How to add Mixed Reality Toolkit(MRTK) to a project?

If you are using HoloLens Seed project, you do not need to follow this step. Seed project already comes with MRTK. Still, it's good to know how to import the MRTK assets for your future projects.
First, you need to download MRTK by going to their github page: aka.ms/MRTKGithub and navigating to releases tab. Scroll down to Assets section and download the tools:
  • Examples
  • Extensions
  • Foundation
  • Tools
Download MRTK Releases.

Add MRTK assets into your project

In your Unity project, select Assets tab and select Import Package > Custom Package from the drop down.
Navigate to MRTK downloaded folders to select and import them into your project.
Once you have MRTK assets imported, a new tab called Mixed Reality Toolkit will appear in your Unity editor. Navigate to new tab and select Add Scene and Configure from the dropdown menu. In your Scene Hierarchy, a new MixedRealityToolkit and MixedRealityPlayspace dropdowns will appear.
MixedRealityPlayspace now includes your Main Camera and the camera is configured for Mixed Reality applications. Camera background is black to render transparent and MixedRealityInputModule, EventSystem, GazeProvider components are now added to your camera.
You can create a new scene to compare the camera settings that has changed by MRTK.
  • You might be prompted to select a configuration. You can choose the default MRTK configuration or if you are developing for an HoloLens device, you can choose the configuration for the appropriate version.