Learning Git would be a big benefit for you, it will aid you when you want to share your project with anyone, not just myself. More importantly, it will give you the ability to manage the changes in your project more appropriately, returning to a previous commit (or branch) when something goes terribly wrong for example.
I have said it several times before but I will say it again, for good measure, start learning/practising with a project which is not your current Portal Reign project. It could be literally an empty scene in a new project, then add a cube, commit the changes, push them to the remote repository and so on. Play/learn with something that doesn’t matter if you trash it/break it/delete it.
Here’s some resources for you to get you started;
On the GitKraken page, scroll down to the videos section, there are some tutorials that will take you through the beginner steps.
The Udemy course I’ve linked you to isn’t about GitKraken, its about using Git with GitHub. This course is free. The instructor is Jason Taylor, he does a very good job of explaining things in this introduction course, he offers paid for courses also which you may be interested in afterwards, see how you get on with the free course first. If you like the instructor and material, Udemy currently have an offer on and his other courses appear to be available for $9.99. I am no affiliate of his, but when I wanted to find out more about Git this was where I started.
There are videos linked from the Git Documentation and a variety of How To’s on the GitHub help site.
Further reading;
Don’t rush this topic - take your time - use dummy projects that can be destroyed - experiment - learn from mistakes. When you’ve got a good understanding of it, then use it with your own project.
Hope this helps