To add the competitions you are interested in to your favorites, press on "Favourite Competitions" in the sidebar on the left side of the home page and then on the "+" symbol.
In the popup window that will appear on your screen, select the events you want and then press on the star so that they are saved to your Favourites list.
Please note that you can select up to 20 events. The list of your favourites will appear on the same section.