No wrong answers here bois, only practice. I'll post an example and then a problem to extend it once per day. The following day I will post a solution. You have to do a pull request to submit your answer. Be sure to put it in a seperate folder.
A pull request (abbreviated as PR) is the ability to request a Git repository administrator to fetch changes you've made to their repository.
The concept is simple: Lisa has a repository of code. Bart would like to help out. Bart creates a copy (what's called a fork) of Lisa's code, makes changes, and submits a pull request to Lisa. She can then decide whether she would like to accept Bart's changes (by pulling the changes from Bart's Git repository - hence the name) or not.
Github provides a comfortable interface to submit pull requests and to accept and merge pull requests. It makes it close to trivial to provide changes and have them easily reviewed and added to an existing code-base.
Github has an excellent pull request tutorial which can walk you through anything not covered here. We begin by creating a repository fork and it's fairly easy to do. When opening the repository on Github, we simply press Fork on the top right.
Once the forking process has finished, Github will host another copy of the repository under our username. However, since it's on the Github server and we don't have access to the server, we actually need to make a local copy on our hard drive. We'll be able to edit it on our computer and sync it with our Github copy.