On the Map View screen, click on the pin drop for that site, and the location information drawer will appear. Click the Add to Favorites link under the location’s name, and it will become a favorite. You can take a similar action on the List View screen by clicking the Add Favorite link. If you need to remove the site from your favorites, click Remove from Favorites link under the location’s name to remove it from the favorites list
Find your favorites by clicking the Favorites Quick Filter button at the top of the Map View screen. Depending on the size of your phone, you may need to scroll to the far right of the Quick Filters to see the Favorites button.