1. Create a Scene Fusion account or log in at scenefusion.com.
2. If you do not have any collaborators on your project, now is the time to add them. To do this, navigate to project 1 from the navbar on the left side of the page, and select the users tab 2. Here you can send invites to users by entering their email address and pressing the invite user button 3.
3. Now select overview from the navbar on the left side of the page, and download the Scene Fusion package for your version of Unity.
4. Once the package is downloaded, you can install it by dragging and dropping it into your Unity project explorer or by going to the Unity file menu -> Assets -> Import Package -> Custom Package and selecting the Scene Fusion package you downloaded.
5. Ensure that all collaborators have the Scene Fusion plugin installed and the same version of the project you will be collaborating on. This can be done through source control or by other means of file distribution.