Your Collections list is where each of your collections is displayed in one place - it's a great way to display each of the different categories and themes your store has to offer.
Collections are a group of individual products - a single product can be featured in multiple collections across your site, and therefore multiple versions of this product are not required in your admin.
Within your Shopify admin, go to Sales Channels > Online Store > Themes.
Click your theme, and select Customize.
Go to the drop-down menu at the top of the page.
Scroll down to select Collection list.
On the left-hand menu, select List collections.
In order to view your collections, they must already exist within your Shopify admin.
Within your Shopify admin, go to Products.
In the drop-down menu underneath, select Collections.
To add a new collection, select Create collection.
To choose how many products you would like to display per collection, use the Products per collection slider to choose a number between 2 and 6 products.