Branches and series

First branch the current trunk repository: bzr branch lp:xubuntu-docs

Then push it back up to the new series name: bzr push lp:~ubuntu-core-doc/xubuntu-docs/wily

Or if you’re using trunk, bzr push lp:~ubuntu-core-doc/xubuntu-docs/vivid

After that, you need to register the new series at https://launchpad.net/xubuntu-docs/+addseries (Register a series) And change the development focus to that new branch/series at https://launchpad.net/xubuntu-docs/+edit if not using trunk.