There was a video made by DragoniteSpam on how to use source control. I think he explains it quite simply how to use it and how to upload your code, but it might be a tiny bit advanced for a beginner.
Link for DragoniteSpam's video:
I would really recommend using this for your other projects as well, because there will be less chance of you losing your progress / project due to some unforseen event, like a power outage, lightning etc.
Good luck on the game jam and Have a good Game Off! :)
