With Shopify, you can use two types of collections: manual and automated
Quoting Shopify documentation:
Manual collection: "A manual collection includes the specific products that you choose. The collection will always contain the same products unless you add or remove them."
In Sc App, you can add/remove products to/off manual collections in bulk. You can refer to the article at the end of this page for more detailed information on the procedure.
Automated collection: "An automated collection uses selection conditions to automatically include matching products. You can add up to 60 selection conditions, and you can specify whether products need to meet all conditions or any condition to be included in the collection.
In Sc App, you can see if a product is associated or not to an automated collection in the Collections property. Refer to the article below for more information.