A library of four hundred products with no structure is a list you scroll. Folders make it a place you navigate.
Two levels, with a sidebar
Main folders live in a left sidebar on the Products page. Subfolders and the products themselves sit in the content pane, visually separated so you can tell a container from an item at a glance.
Two levels is the whole depth. Kitchen then Faucets is a folder path; Kitchen then Fixtures then Faucets then Wall Mount is a filing system nobody maintains.
Imports file themselves
When products arrive through any import route, each preview row comes with a suggested folder already selected, such as Kitchen then Faucets or Primary Bath then Tile.
Change any suggestion in the preview before you save. If the suggested folder does not exist yet, it is created when you save, so you do not have to build the tree in advance.
Bulk import
Paste up to ten product links at once, one per line. You get ten preview rows, each with its own suggested folder, each independently editable. Save them together.
This is the intended way to clear a client's inspiration email or a designer's spec list.
Moving things later
Select products with the checkboxes and move the selection into a folder. Renaming a folder does not touch the products inside it, and it does not touch any spec sheet, because spec items carry their own copies of the product fields.
Filtering and search
Folder is one filter among several: you can also narrow by location, manufacturer, and how a product got into the library. Search runs across whatever the filters have left, so folder plus a search term is the fast way into a large library.