No one has ever explained properly what it is.

GitHub is a freemium service for git repositories, which is now owned by Microsoft. There's a Wikipedia article about it. GitHub is probably the most used git provider, and especially many FOSS projects choose it for the community.

No one has ever explained what it does.

It lets you create git repositories in private or public mode (visible to others) and offers a few nice management features, like pull requests, task boards, issues, Wiki, project overviews, team management, etc.

Also it looks pretty complicated to set up.

Just enter a username and email and you can use it (aka store your repositories on GitHub as opposed to a different provider or your own git server). Many pages, like Hashnode, offer you to authenticate using the GitHub account, which means fewer passwords to remember and less typing, if you are logged-in to GitHub all day anyway. If you don't like GitHub, there are other services, too. For example GitLab, Bitbucket, Azure Repos, ...

Can any of you sharp minded people help me out?

For my sharp mind, your complaints sound more like you don't know git - or code versioning - than GitHub. Am I right? I recommend reading articles by industry leaders, like Atlassian (e.g. this one). Alternatively, I can summarize it for you.

If you have further, more concrete questions, just reply below!

There are some aspects:

• Git

...is a tool to control the history of your code and to collaborate with other people on the same codebase. There are several tools for that, but git is very popular, and honestly just more powerful than subversion.

I would say knowing how to use a version control tool is essential knowledge for any programmer who wants to outgrow the solo hacker stage. And git is the best choice for version control.

It can be hard to get started with git. But there's a lot of material online.

• Github

Git is used to share code. For that it helps to have a central place where different people can reach the code. Github is one of those places where you can do so for free. It's probably the most popular one, but there are others (bitbucket, gitlab).

Making an account and getting started is pretty easy, after you have learned how to use git. Just register, make a project, and use git to send your code to github.

• Open source

Github is commonly used for code that is 'open source'. This means that anyone can see and use your code. They may even help you with your project.

Whether this is something you want, depends. There are other topics about that: why open source is important / 12 reasons to contribute / what stops developers from contributing.

Note that Github can also be used without making your code open source! These days, it's free to make private (non-open) repositories for your projects (maybe not for commercial use? I'm not sure).

To summarize, Git is hard at first, but very useful. Github is easy once you know git, but is less essential - there are pros and cons.