After you created a list of territories, you can set working territory for your workers.
Open page Settings → Users.
You will see a list of all your users.
Open user you need. The page with his settings will be opened.
At the bottom under permissions, you will see a field with his territory.
Click on this field and you'll see a list of all available territories in the dropdown menu. Choose the territory you need and click on the Save and close button.
This way you can distribute your workers to all territories.