Branches are pointers to commits. The default branch is usually main or master. Create a branch to experiment without affecting the main branch, then merge it back when ready. This is how teams work in parallel on different features without conflicts.

$ git branch                 # list branches
$ git branch <name>          # create a branch
$ git checkout <branch>      # switch to a branch
$ git switch <branch>        # modern way to switch (git 2.23+)
$ git branch -d <branch>     # delete a branch

Each branch is independent—changes on one branch don't affect others until you merge. Branches are cheap to create; the recommended workflow is to create a branch for each feature or bug fix, work on it in isolation, then merge it back to main once it's tested.