@mashalibby you have to go to the store gallery itself, like Walmart or Target etc. Once you open you'll see the your list circle on the bottom right. If you are scrolling down the page it disappears, but will float into view once you start scrolling back up the page.
When you open a retailer's gallery after selecting products you will see the grid icon. This is your shopping list this is also how you remove items from your list.