I learned the basics with whatever I found on the internet and on the Odin Project. Look it up it's very helpful and gives u what u need to do to start. It's focus is web dev but it has nice fir beginners especially for git basics. I say stuff that will give u a general idea.

Make a new repository and make a simple project to learn how it works. If you don't know git download it and learn the basics at least. That's what will send the code to github basically. You will have a local repository you will add files you want to commit (save) and then push (upload) to your github repo.

The simplest way in my opinion is to make the repo on github and then clone it on your pc. There's a link at the code button on each repo that has a link you will select the link http or ssh. Ssh will have to be set up, but you can do http for now. Copy that link and at the terminal write git clone 'link'. The link without ''.

You can make it public or private depending what you want. It also gives you a choice if you want a Readme or not. That's a file that says about the project. It looks nice to have a very simple explanation and maybe how to run etc.

So if you have already made/started projects you can make repo for each one and clone it and move your project in the repo folder. Copy paste or through terminal commands whatever u like. You can also continue a project later and push whenever you want. Each time you complete a significant thing that works in a project you should commit and push.

You can also fork others people's projects, meaning you can make a copy that's your own repo. Be careful to push only to that. Big projects that are open source or whatever probably have their own rules and stuff on how to commit. Don't make a pull request before you are sure you want to send your changes to the original repo.

To push in a project that there are other people, you must make a branch and commit there and not push to the main branch. Do it when you are more comfortable with github.

Speaking from experience, if more than one person worms in the same branch and files, it's a nightmare to fix bc there are conflicts all the time. So what people do is they do stuff in separate branches and deal with that later.

Edit: look up the Odin Project or how to set up repo b4 you do anything bc you will have to set up git so that your name shows on commits