For this experience, use the Learn Git Branching site to get comfortable with basic ideas of git.
At a minimum, go through the 4 introductory levels in the Main area:
As well as the 7 levels explaining Push and Pull in the Remote area:
To get started using the site, just read the first dialog box that appears, then click the green right arrow button to advance to the next dialog box.
You do not have to submit anything for this experience, but your knowledge of git branching will be assessed in class, so be sure to finish this experience.