forest branchcommand is at the center of what your Forest Admin development workflow should look like. As explained on this page, it allows you to manage your UI, a bit like you would use git's branches for your code.
forest branchcommand has 3 uses, depending on how you use it:
forest branch, like so:
LayoutChange(s)(i.e. changes in your UI) that you've made on that branch: to make this possible, a branch needs an origin, which is the state of the layout you started from and made those
LayoutChange(s)on. This is why you need to have a production environment (ideally) or simply a remote environment: that environment will serve as origin to your branches.