For a local setup you first need to install Unity 3D. Plase note that you must use version 2017.4.26f1 LTS. You can install it by first installing Unity Hub and then selecting the correct version in the Installs section.
Furthermore, make sure that you have installed the Windows 10 Fall Creators Update.
If you have any issues have a look at the official Microsoft documentation: https://docs.microsoft.com/de-de/windows/mixed-reality/install-the-tools. Please note, that their documentation is for a newer version of the MixedRealityToolkit. So be careful when doing any updates as it will probably break the setup.
Unity 3D has to be adjusted to work well with Git. Here is an article with all the necessary details to get you started: https://thoughtbot.com/blog/how-to-git-with-unity
If you want to import a different model, created by the Getaviz generator, put the model.html and the metaData.json into the Assets/StreamingAssets folder. Also make sure to include the source code for your software artifact in Assets/StreamingAssets/src/.