The catalog page within your theme will list all of the visible products currently on your store.  This page will have the URL - your-store.com/collections/all.  By default, the products which appear on this page will be sorted in alphabetical order.  However - you can create a collection to control the order in which these products are displayed.  

1. From your Shopify admin, go to Products > Collections.

2. Click Create collection.

3. Create the collection:

   1. Give your collection the title All.
   2. In the Collection type section, select Automated.
   3. Set the product condition Product price is greater than $0.
   4. Optional: To hide products that are out of stock, add the condition Inventory stock is greater than 0 as well.

4. Click Save.

5. Now that you have created your All collection, you can sort the products within it. Scroll to the Products section and select an option from the Sort drop-down menu.

   If you select Manually, then you can rearrange your products by using their drag and drop handles ⋮⋮.

6. If you want to change the title of your All collection, then you can edit it now that the collection has been created. It is important, however, that the handle of the collection remains set as all. You can confirm this by scrolling to the Search engine listing preview section, and clicking Edit website SEO.

   In the URL and handle text box, you should see a URL that ends in /all.

   If the URL ends in something different, then change it to /all, and click Save.

The above steps have been taken from Shopify's guide to creating this collection - please see their original documentation here.