1. From Setup, enter Territories in the Quick Find box, and then select the territory settings.
2. Enable Filter-Based Opportunity Territory Assignment.
3. If your organization is using the Apex code Salesforce provides, first create the class and then return to this Settings page and enter the class name:OppTerrAssignDefaultLogicFilter. If you opt to use your own code for the Apex class, you’ll come back and enter the name of the class that you create.
4. If you want to run the filter-based opportunity territory assignment job when opportunities are created, select that option.
5. Save your settings.