Your sites can be grouped together into a branch.
To create a new branch, go to the Plan > Shift allocation (Branch) screen. Choose the cog icon at the top of the page next to the names of your current branches.
You will then see a pop-up screen which lists your branches, and in the bottom left there's a blue button to create a 'New branch'.
Then just choose a name and click 'Create'.
Once you've created a new branch you'll want to link certain sites to it and also link workers to it. For more info on these processes, click the links below: