Best explanation of this topic I have found anywhere. The sidenotes fill in exactly the gaps I had.

Git & GitHub Masterclass
Version control, from an empty folder to a merged pull request.
A complete-beginner path through Git, GitHub, and GitHub Desktop — commits, branches, merges, remotes, and pull requests, with nothing assumed. Ends with your first real open-source contribution and a full end-to-end capstone.
Read on your Kindle or e-reader
Download the EPUB and read offline — perfect for the train. Works on Kindle, Kobo, Apple Books & more.
00Getting Oriented6 capsules
Getting Oriented — 6 chapters.
01Why this masterclass?conceptfree11 min02Why should you care about Git & GitHub?intuitionfree10 min03How this book is structuredconcept🔒10 min04Git vs GitHub — the crucial distinctionconcept🔒10 min05Is Git/GitHub only for code?concept🔒10 min06What is a terminal, and do I need it?concept🔒12 min01Version Control Foundations5 capsules
Version Control Foundations — 5 chapters.
07What do we mean by version control?concept🔒11 min08How long can you go without learning Git?intuition🔒12 min09Common rookie mistakes to avoidintuition🔒11 min10Git/GitHub alternativesconcept🔒11 min11GitHub Desktop — the easy way inconcept🔒11 min02Meet the Team & the Plan2 capsules
Meet the Team & the Plan — 2 chapters.
12About Team Vizuaraconcept🔒10 min13What we'll cover in the rest of the courseconcept🔒9 min03All About Git10 capsules
All About Git — 10 chapters.
14What is Git?concept🔒12 min15How Git version control worksconcept🔒11 min16The repository — where history livesconcept🔒13 min17Installing Gitproject🔒12 min18Git basic commands: init, add, commit, statuscode🔒13 min19Pushing a local repo to GitHubcode🔒13 min20What are Git branches?concept🔒12 min21Merging branchescode🔒10 min22Git pull — staying in synccode🔒11 min23Git fork — your own copy of someone's repoconcept🔒13 min04All About GitHub3 capsules
All About GitHub — 3 chapters.
24What is GitHub?concept🔒12 min25Anatomy of a GitHub repository pageconcept🔒12 min26Pull requests — how change gets reviewedconcept🔒11 min05GitHub Desktop, Step by Step5 capsules
GitHub Desktop, Step by Step — 5 chapters.
27GitHub Desktop — install and sign inproject🔒10 min28Committing changes in GitHub Desktopproject🔒12 min29Pushing and pulling with GitHub Desktopproject🔒12 min30Branching and merging in GitHub Desktopproject🔒12 min31Resolving conflicts in GitHub Desktopproject🔒13 min06For Students, Researchers & Pros3 capsules
For Students, Researchers & Pros — 3 chapters.
32GitHub for studentsconcept🔒12 min33CI/CD with GitHub Actions — Part 1deep-dive🔒11 min34CI/CD with GitHub Actions — Part 2deep-dive🔒12 min07The Real World & Open Source6 capsules
The Real World & Open Source — 6 chapters.
35GitLab and the wider ecosystemconcept🔒10 min36Cool GitHub repos worth exploringconcept🔒10 min37Do all companies use GitHub?concept🔒11 min38Do all professionals use GitHub?concept🔒12 min39Making your first open-source contributionproject🔒13 min40Capstone: putting it all togetherproject🔒12 minRatings & reviews
445 readersDense but never confusing. Every chapter builds cleanly on the last — you can feel the care in the structure.
A few sections moved fast for me, but re-reading with the figures open made everything land. Highly recommend.
This is the resource I wish I had when I started. Clear mental models, zero fluff.