Improve Repository Documentation Structure

[kyracnh]

Currently, the README provides a brief intro, but the documentation structure could be improved for clarity and usability. For example:

Add a table of contents in the README linking to different sections (Beginner, Intermediate, Advanced).

Provide clearer guidance on how to navigate translations (en, es, jp, ru, zh, etc.).

Highlight contribution guidelines (how someone can add translations, corrections, or new sections).

[RobertLRead]

Hi, thanks for your issue. It seems to me there are already links and a table of contents in the README, so I am not sure what you are asking for there. I have, however, just added a short "CONTRIBUTING" section to clarify that.

I'm not sure how to clarify navigation between the translations---do you have a suggestion?