Under the same Shipping and Delivery page in Settings, click on Order Routing Rules in the Order routing section.
Make sure that you add the Use Ranked Locations rule at the top.
Click edit on the User ranked locations rule and make sure Best Buy In-Store Pickup is at the bottom of the ranking. This will ensure this location will only be selected at checkout if the In-Store pickup option is selected by the customer.
Voila! You are all set up! Now you can checkout your storefront and see Best Buy In-Store Pickup in action!