The git-wiki project is composed by 3 different repository:
git-wiki-theme: This is the repository of the theme that implements the wiki functionalities. You would have not fork it unless you need to send a Pull Request or create your wiki project from scratch.
git-wiki-skeleton: This is the repo that you should fork or use as a template. It uses the jekyll remote theme functionality that allows you to create your own wiki based on git-wiki-theme. By using the remote functionality you can automatically keep your wiki always updated with latest features from the git-wiki-theme, but you can also fully customize it.
git-wiki: This is the documentation repository and website of the git-wiki-theme project. You would have not fork it unless you want to contribute to the git-wiki project documentation.
The easier and faster way to use git-wiki is the "skeleton" method.
You don't need to install anything locally!
Simply fork/clone skeleton repo or click on the "Use this template" button to create your copy of the skeleton project.
Edit _config.yml and other pages as you need and then deploy it on GitHub/Gitlab Pages.
Done! Now wait that your page will be published and you're ready to wiki!
You can use it with the Jekyll "remote_theme" feature or fork/copy the master branch and start your wiki in just 1 minute.
Instructions and full documentation: http://drassil.github.io/git-wiki