In order to set a favorite exercise in the Leg Trainer app, go to the menu by tapping the icon in the upper left corner or swiping the screen from the left to the right.
Select “All Exercise Videos”. Open your favorite exercise by tapping on it. There is a star in the top right corner - tap it to set the exercise as one of your favorites.
View all favorite exercises:
Go to the menu again and select "All Exercise Videos". Tap the filter icon in the upper right corner and set the star as your filter. All your favorite exercises are shown.