If you don't know how to use it, well, now's a good time to learn! Here are some useful links to help you learn:
In addition to having your Git repository (repo) on your own computer, you can have your repo hosted on several different sites, including Github, Bitbucket, and Gitlab. You can synchronize between the repo on your computer and on a third-party site. Since your Git repo contains a full history, it's not very important (technologically) which website, if any, you use. They each have pluses and minuses.
You can create a repo called yourusername.github.io , and put web pages in that repo. It will then be accessible as http://yourusername.github.io Each software repo of yours can also have an accompanying website, using a new branch called gh-pages. The project's website will then be http://yourusername.github.io/projectname
For example, let's say that your username is myusername, your repo is named lm-paper and you have a collaborator named Bob, who has a Bitbucket ID of bobusername :
The README.md file gives an overview of your Git project, including the software name, how to install/compile, command-line usage, copyright, etc. The .md suffix indicates that it is in the Markdown format, which is like plaintext, but includes some simple additions to make it look nice in your web browser. Here is the Wikipedia article on Markdown
The LICENSE.txt file tells others how they can use your software. If you don't specify a license, then you're not granting the right for others to use your code. Consider using a Free software license to encourage others to use and build upon your software.