You will need to press shop list on the list you wish to shop from.
The filter options will sit towards the top of your screen.
Once the list has fully loaded, by using the filter you will be able to drill down into a specific category. (As shown in screenshot below)
You are also able to sort your basket as well.
You can also change the way in which the products display. As standard they are set to display in a list however you can change them to view in a tile format. (see below screenshot)