If you click on a pin and scroll down the card, there is a “Favorite” button. Clicking it will add it to your Favorites list which can be accessed at the bottom

If you click on a pin and scroll down the card, there is a “Favorite” button. Clicking it will add it to your Favorites list which can be accessed at the bottom of the search results list. The list syncs to your Mac Maps app too. The interface is not the most intuitive but it’s there.