Click the button at the top right of the start screen, press the magnifying glass in the upper task bar and then enter the location into the search box. Tap the desired location on the search results, which will save it as a favourite.
To delete favourites or change their order, please press the Edit button ("pen") at the bottom right. The deletion is done via the Delete button ("trash") next to the name. The button right next to it allows you to sort their order by dragging & dropping.