Checking out a branch

Now that the branch has been created you have to do a "Check out". If you've followed this guide chances are that you're already in the branch you want to check out (otherwise you can find it here).

Just click on the button "Check out", and choose to either use the pre-generated GIT command, or if using SourceTree, choose "Check out in Source Tree". This will automatically make Source Tree to prompt for checking it out. Very convenient!

The term "check out" in GIT can be confusing. In GIT, "check out" (in the GIT client, the command "git checkout <target-branch>") just means "switch from my current branch to <target-branch>". You can use this command to switch between branches on your local development machine. Normally in GIT, it has nothing to do with downloading source from a remote repository (or with "locking" a source file so that no one else can edit it).
Bitbucket has added a "Check out" button (see below), that downloads the new branch from the remote repository and then checks it out (switches to it) locally.