[ColdHawaiian]

The key concept that you need to truly understand how Git works is to just remember that Git is just a tree of commits, with temporary and movable Post-it notes attached. (The Post-it notes representing branches and other references).

[mrtngslr]

That's a good image. The key difference to Mercurial is then that Mercurial's tree of commits don't need Post-it notes. The tree can stand on its own without extra branch labels. You can add them (see bookmarks) but they're an optional feature.