It’s important not to conflate git and github. Cloning is a git operation. Forking is a github operation.
I would recommend reading the excellent pro git book to understand how git works from the ground up: https://git-scm.com/book/en/v2
I’m not aware of a similar guide to learning github but I think it will be much easier to pick up once you have a better understanding of what git provides on its own.
Unless you need to interact with other people, you can always just clone the repo, work locally, and create your own github repo (without forking) to act as a remote and backup.
It’s important not to conflate git and github. Cloning is a git operation. Forking is a github operation.
I would recommend reading the excellent pro git book to understand how git works from the ground up: https://git-scm.com/book/en/v2
I’m not aware of a similar guide to learning github but I think it will be much easier to pick up once you have a better understanding of what git provides on its own.
Unless you need to interact with other people, you can always just clone the repo, work locally, and create your own github repo (without forking) to act as a remote and backup.