With Territory hierarchies, managers have flexibility in creating Territories by adding multiple sub-territories for back-office users and their field team. Reps and back-office users can be assigned to multiple territories, and they can also be assigned to any level in the hierarchy. This feature allows admins to limit other back-office users to a territory so that they are only able to see data from their respective territories.
This article covers the topic of how to assign back-office users to territories, or sub territories. Take a look at the article on the link, if you want to learn How to assign reps to territories.
1. Open the back-office user profile by clicking the Gear icon, Settings, Back-office users.
2. Select the user whose territory access you want to restrict. In their profile, under Restrict access to territories, a drop-down menu will appear from which you can choose your Territories. 
Check the box next to the Territory you want to assign. If you only choose to assign certain sub-territories, when you do that, they will be marked with the checkbox, and the Territory it derives from will be marked with a line.
The user can see the root territory and the sub-territory the assigned territory comes from, but not the Territories they're not explicitly assigned to. In other words, only the territories marked with a blue check box; in this case, territory West and sub-territory Coast will be assigned.
Result
The back-office user in question will see only the Places in the territories assigned to them.