How do i save the selected item in cart


Im really stuck at the place where I am unable to search what should i search :frowning:
I am doing a school project on restaurant app and i am stuck at the cart page where i add a single item i am able to see that item when i go back to menu page to add another the item disappears :open_mouth: how do i make him stay there unless & untill the user removes it from cart. please help badly stuck here :frowning: